JPH05325197A - Information recording medium - Google Patents

Abstract

PURPOSE:To perform a notation by means of the small number of bits by a method wherein a pair of wobble marks which is provided with mutually opposite tracking-error-detection polarities is formed on two adjacent tracks on a recording medium and track addresses are described on two adjacent tracks each by means of the same pattern. CONSTITUTION:Pairs of wobble marks 1, 2 and 5, 6 are arranged so as to obtain respectively opposite detection characteristics; the recognition marks 5, 6 on tracks T1, T2 are constituted of the same pattern. A tracking-error signal can be found from the difference in an amplitude between the pair of wobble marks which are read out by means of a head. Error signals in the tracks T1, T2 display a rightward falling negative polarity; error signals in tracks T3, T4 display a rightward rising positive polarity. Consequently, both can be separated unequivocally by means of a tracking control polarity even regarding the same pattern. As a result, it is possible to describe the number of tracks which is twice as many as that in conventional cases by means of the same number of bits in conventional cases.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium having a high information retrieval function such as an optical disc and a magnetic disc.

[0002]

2. Description of the Related Art In recent years, the capacity of information recording media such as optical disks has been increasing.

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

FIG. 5 shows the structure of a conventional information recording medium. In FIG. 5, 101 and 102 are wobble marks, which indicate the center line position of the track T1. Reference numeral 104 denotes a recorded information area, which is provided along the center line (one-dot chain line in the figure) of the track T1. Reference numeral 103 is a track address, and the track T1 is replaced with another track T.
2 and T3. Tracks T1, T2,
The track addresses at T3 are all different.

The operation of the information recording medium having the above structure will be described below.

When information is recorded in or reproduced from the information recording area 104 provided on the track T1 by using the recording / reproducing head, the recording / reproducing head always uses the track T.
Must be on the centerline of 1. Therefore, the recording / reproducing head first identifies the track address 103, and then performs tracking control so that the reproduction amplitudes of the wobble marks 101 and 102 become equal. Then, the recording / reproducing head records information in the recording information area 104. (For example, Y.Nakasima, et.al., "86mmMagnet
o-optical Disk Drive ", Proc. of SPIE, vol.1316, p
p.16-29; Nakajima et al., "86mm magneto-optical drive", Proceedings of SPII, Volume 1316, Volume 16-29
page).

[0007]

However, in the above-mentioned configuration, the number of bits required to describe the track address increases as the number of tracks increases, and as a result, the information recording area is compressed. I had.

In view of the above problems, the present invention provides an information recording medium in which a track address is written with a smaller number of bits.

[0009]

In order to solve the above problems, the information recording medium of the present invention is provided with a pair of wobble marks having opposite tracking error detection polarities on two adjacent tracks, and the track address is , Each adjacent two tracks are described in the same pattern.

[0010]

With the above-described structure, the present invention makes it possible to perform substantially unique addressing on two tracks having the same pattern, depending on the polarity of the tracking control. As a result, the same number of bits as the conventional one can be used. It is possible to describe the address with the number of tracks twice as large as the conventional one.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An information recording medium according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of an information recording medium in an embodiment of the present invention. In FIG. 1, 1, 2,
Reference numerals 3 and 4 are wobble marks, reference numerals 5 and 6 are track identification marks, and reference numeral 7 is an information recording area, each of which has substantially the same function as that of the conventional example. The difference from the conventional example is that the wobble mark pairs 1 and 2 and the wobble mark pairs 3 and 4 are arranged so as to obtain opposite detection characteristics, and the track identification marks 5 provided on the tracks T1 and T2. , 6
Means that they are constructed in exactly the same pattern.

The operation of the information recording medium having the above structure will be described below with reference to FIGS. 1 and 2.

First, FIG. 2 shows a tracking error signal collected from the information recording medium shown in FIG. The tracking error signal is obtained from the difference between one amplitude and the other amplitude of the wobble mark pair read by the recording / reproducing head. In FIG. 2, the tracking error signals on the tracks T1 and T3 show a downward-sloping polarity (which has a negative polarity). On the contrary, the tracking error signals on the tracks T2 and T4 have a downward-sloping polarity (positive polarity). ) Is shown. Tracks T1 and T2 are provided with track identification marks 5 and 6 having the same pattern as shown in FIG. 1, but the tracking polarities are opposite to each other as shown in FIG. Here, when the negative polarity tracking control is executed, the recording / reproducing head is drawn to the track T1, and when the positive polarity control is executed, it is drawn to the track T2. Therefore, even if the patterns are the same, they can be uniquely separated by the polarity of tracking control.

As described above, according to the present embodiment, the wobble mark pairs 1 and 2 and the wobble mark pairs 3 and 4 are arranged so as to obtain the opposite detection characteristics, and are exactly the same on the adjacent tracks T1 and T2. By providing the track identification marks 5 and 6 composed of patterns, as a result, an address having the same number of bits as the conventional number and twice the number of tracks as the conventional number can be described.

In this embodiment, the track identification mark is equivalent to the conventional track address, but the track identification mark is not limited to the track address and may be applied as a gray code address provided for track seek.

A second embodiment of the present invention will be described below with reference to the drawings. 3 and 4 are configuration diagrams of an information recording medium showing a second embodiment of the present invention.

In FIG. 3, reference numerals 5 and 6 are track identification marks, and 7 is an information recording area. The above is the same as the configuration of FIG. The difference from FIG. 1 is that wobble marks 1, 2,
3 and 4 are formed as wobble marks 11, 12, and 13 by overlapping wobble marks of adjacent tracks.

The operation of the information recording medium having the above structure will be described below. First, in FIG. 5, that is, in the conventional configuration, when the track density is increased, the wobble marks of adjacent tracks approach each other, and a new problem occurs that the tracking error detection sensitivity is lowered due to mutual code interference. However, in the configuration of FIG. 1, since the wobble mark 2 and the wobble mark 3 provided on the tracks adjacent to each other substantially function as one wobble mark, even if the track pitch is narrowed, both of them overlap each other. Therefore, the tracking error detection capability is hardly reduced. Therefore, as shown in FIG. 4, the wobble marks 2 and 3 may be formed as one wobble mark 11.

[0020]

As described above, according to the present invention, the wobble mark pairs on two adjacent tracks have opposite tracking error detection polarities, and the adjacent two tracks are provided with the same pattern of tracking addresses. It is possible to describe an address with the same number of bits as the number of tracks twice that of the conventional one.

[Brief description of drawings]

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

FIG. 2 is an operation explanatory diagram in the same embodiment.

FIG. 3 is a configuration diagram of an information recording medium in a second embodiment of the present invention.

FIG. 4 is a configuration diagram of an information recording medium in a second embodiment of the present invention.

FIG. 5 is a schematic view of a conventional information recording medium.

[Explanation of symbols]

 1, 2, 3, 4 Wobble mark 5, 6 Track identification mark 7 Information recording area

Claims (3)

[Claims] 1. A track group for recording information, each track including an information recording area provided along a center line of the track, a track guide mark representing the center line of the track, and the track. An information recording medium having a track identification mark for distinguishing it from other tracks, wherein the track guide marks in two adjacent tracks have opposite tracking error detection polarities, and the track identification marks are adjacent to each other. An information recording medium having the same pattern for every two tracks. 2. The information recording medium according to claim 1, wherein the track guide mark comprises a pair of wobble marks. 3. An information recording medium according to claim 1, wherein one of two pairs of wobble marks provided on tracks adjacent to each other is formed to overlap each other.