JP2684969B2 - Optical disk media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc medium for high density recording and reproducing of information by using light.

[0002]

2. Description of the Related Art An optical disk medium is an information recording medium capable of recording information at a high density by forming a pit train on a track using a minute light spot.
In order to enable this high density recording and reproduction, a track guide groove is formed in advance on the optical disc medium. The optical disk device can perform a stable tracking operation by optically detecting the guide groove.

FIG. 5 shows a track form of a conventional optical disk medium. In the form shown in FIG. 5A, the guide groove 2 is spirally formed on the entire surface of the optical disk medium 1. The recording tracks include a groove recording track in which a pit row is formed in a concave portion in the guide groove 2 and a land recording track in which a pit row is formed in a convex portion between the guide grooves. An example of the land recording type optical disk medium is disclosed in Japanese Patent Laid-Open No. 63-112839.

In order to improve the recording density in such a conventional optical disc medium, it is necessary to form the guide grooves 2 at a high density, which makes it difficult to manufacture the optical disc medium. Therefore, a land / groove recording method is being studied in which both the concave portion of the guide groove and the convex portion between the guide grooves are simultaneously used as recording tracks. According to this method, the density of the guide groove can be reduced to 1/2 or less of the recording track density.

[0005]

However, if the form of the conventional optical disk medium is used as it is, FIG.
As shown in (b), the groove recording track 4 and the land recording track 5 on the optical disc medium 3 become a double spiral. In order to perform continuous data recording with this structure, it is necessary to use a plurality of light spots and perform a complicated track jump operation.

Therefore, an object of the present invention is to provide an optical disk medium of a land / groove recording system capable of high density recording and reproduction without performing a complicated operation such as a track jump.

[0007]

An optical disk medium according to the present invention has a groove recording track in which a concave portion of a guide groove is a recording track and a land recording track in which a convex portion between adjacent guide grooves is a recording track. , Groove recording tracks and land recording tracks are alternately connected to form one spiral recording track.

The groove recording tracks and the land recording tracks are alternately arranged, for example, for each circumference to form one spiral recording track.

Further, it is desirable to provide a switching section for indicating switching at the connecting section between the groove recording track and the land recording track. The switching portion is formed of, for example, a flat portion having no guide groove or a predetermined pit pattern.

[0010]

Since the spiral recording track of the optical disk medium has a form in which groove recording tracks and land recording tracks are alternately arranged, high density recording and reproduction of information can be performed only by continuously scanning the light spot. it can.

[0011]

Embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a schematic track configuration diagram showing an embodiment of an optical disk medium according to the present invention. As shown in the figure, in the optical disk medium 7 of the present embodiment, the groove recording tracks 8 (solid lines) and the land recording tracks 9 (broken lines) are alternately and continuously connected for each circumference, and as a whole, one optical disk medium is formed. It constitutes a spiral track. The groove recording track 8 is formed in a concave portion inside the guide groove, and the land recording track 9 is formed in a convex portion between the guide grooves. Therefore, the guide groove of the optical disk medium 7 is 1 as shown by the solid line curve in FIG.
It is formed discontinuously every lap.

The guide groove does not have to be a continuous groove, but may be an intermittent groove such as a pit row as long as it has a guide function.

FIG. 2 is an enlarged view of the portion a shown in FIG. 1, and is a schematic diagram showing a detailed structure of a connecting portion between the groove recording track 8 and the land recording track 9. Here, two groove recording tracks 8-1 and 8-2 and 2 are used.
Each connection portion with the land recording tracks 9-1 and 9-2 of the book is illustrated, and both ends of the groove recording track 8-1 are A1 and B1, both ends of the groove recording track 8-2 are A3 and B3, and the land. Both ends of the recording track 9-1 are A2
, B2, and one end of the land recording track 9-2 is indicated by A4.

As shown in the figure, the land recording track 9-
The end A2 of No. 1 and the end B1 of the groove recording track 8-1 are connected to each other with the switching portion having the length L sandwiched therebetween, and form one continuous recording track. Similarly, between the end A3 of the groove recording track 8-2 and the end B2 of the land recording track 9-1, between the end A4 of the land recording track 9-2 and the end B3 of the groove recording track 8-2, They are connected by a switching unit having a length L. The connection between the other land recording tracks and the groove recording tracks is the same. The switching portion in this embodiment is a flat portion having no pits, is used for detecting the tracking control switching timing as described later, and has a length L so as to meet the purpose.
Is set.

In order to record or reproduce information on the optical disc medium 7 having such a structure, it is necessary to switch the tracking control between the groove recording track 8 and the land recording track 9.

FIG. 3 is a block diagram showing a tracking control circuit of an optical head for recording or reproducing on the optical disc medium of this embodiment.

In the figure, the optical head 10 is generally
The laser beam is focused and a light spot is irradiated onto the optical disc medium 7 to record information, and the reflected light is used to reproduce, track, and focus information.

The push-pull method is employed here for the tracking control, and the actuator drive circuit 14 drives the optical head 10 in accordance with the servo signal to keep the light spot following the track. In the push-pull method, the servo operation to the zero cross position is performed, but the polarities of the servo signals are reversed between the land recording track and the groove recording track. Therefore, the switching signal detection circuit 11
The change between the land recording track and the groove recording track is detected by means of the polarity change circuit 13
Is controlling.

The switching signal detection circuit 11 includes an optical head 10
A switching portion (here, a flat portion) having a length L formed at a connection portion between the land recording track and the groove recording track of the optical disc medium 7 is detected by the read signal from the.
Various detection methods can be considered. The absence of the guide groove may be detected, or the absence of pits existing at predetermined intervals in the recording track may be detected.

Due to the presence of this switching portion, the switching timing of the land recording track and the groove recording track can be detected reliably. This switching timing can be detected by detecting the rotational angle position of the optical disk medium 7, but by providing a switching portion (flat portion) having a predetermined length L at the switching position, a more reliable switching operation can be performed. it can. When the switching signal detection circuit 11 detects the flat portion, the detection signal is output to the polarity switching circuit 13.

The polarity switching circuit 13 is the polarity switching circuit 1
According to the detection signal from 3, the polarity of the servo signal from the tracking error detection circuit 12 is switched. This enables the tracking operation of the optical disk medium 7 in which the groove recording track 8 and the land recording track 9 are mixed.

In this way, the switching signal detection circuit 1
The polarity of the tracking servo signal can be switched every time 1 detects the switching portion, and the data of the groove recording track 8 and the data of the land recording track 9 can be alternately recorded and reproduced.
Further, in the above processing, one recording track continuous in a spiral shape is scanned by the optical head 10, and scanning can be performed by a single optical head 10. Further, it is not necessary to perform an unnecessary track jump operation.

FIG. 4 is a schematic enlarged view showing another structural example of the connecting portion in another embodiment of the present invention. As shown in the figure, a pit row having a predetermined pattern is formed in each of the connecting portions 15 between the land recording tracks 9 and the groove recording tracks 8. This pit row shows a switching portion between the groove recording track 8 and the land recording track 9. That is, when the light spot of the optical head 10 scans the connection portion 15, the switching signal detection circuit 11 detects a predetermined pit pattern of the switching portion, and the switching timing between the land recording track 9 and the groove recording track 8 is thereby detected. Detect.

Since the connecting portion between the groove recording track 8 and the land recording track 9 is formed of a predetermined pit pattern, the tracking servo system can be switched more reliably regardless of the length of the connecting portion. .

Incidentally, the structure of the connecting portion is flat as shown in FIG.
Alternatively, the pit structure shown in FIG. 4 is used, but another structure may be used. Further, the connection portion detection based on the rotation angle of the optical disk medium 7 may be used together.

Further, in this embodiment, the groove recording tracks and the land recording tracks are alternately arranged every one turn, but
Of course, it is not limited to every one round, but may be every half round, or may be arranged every other desired round.

[0028]

As described in detail above, since the optical disk medium according to the present invention is spirally formed as one continuous recording track by connecting group recording tracks and land recording tracks alternately, It is possible to record and reproduce information at high density simply by continuously scanning the light spots. Further, since the complicated operation such as the track jump does not have to be performed, the control system becomes simple.

[Brief description of the drawings]

FIG. 1 is a schematic track configuration diagram showing an embodiment of an optical disc medium according to the present invention.

FIG. 2 is a schematic enlarged view for explaining a configuration of a connecting portion between a group recording track and a land recording track in the present embodiment.

FIG. 3 is a block diagram of an optical head tracking control circuit for recording or reproducing information on the optical disc medium of the present embodiment.

FIG. 4 is a schematic enlarged view for explaining a configuration of a connecting portion between a group recording track and a land recording track in another embodiment of the present invention.

FIG. 5 is a schematic diagram for explaining track configurations of a first example (a) and a second example (b) of a conventional optical disc medium.

[Explanation of symbols]

 7 optical disk medium 8, 8-1, 8-2 group recording track 9, 9-1, 9-2 land recording track 10 optical head 11 switching signal detection circuit 12 tracking error detection circuit 13 polarity switching circuit 14 actuator drive circuit

Claims (4)

(57) [Claims] 1. An optical disk medium having one spiral recording track, wherein the recording track has a groove recording track whose concave portion is a recording groove and a convex portion between the adjacent guiding grooves. Land recording tracks serving as tracks, and the groove recording tracks and the land recording tracks are alternately arranged, and the groove recording tracks and the land recording tracks are provided at a connection portion between the groove recording tracks and the land recording tracks. An optical disc medium provided with a switching unit capable of detecting switching with a track. 2. The optical disk medium according to claim 1, wherein the groove recording tracks and the land recording tracks are alternately connected for each circumference. 3. The optical disk medium according to claim 1, wherein the switching portion is a flat portion where the guide groove does not exist. 4. The optical disk medium according to claim 1, wherein the switching section is formed of a predetermined pit pattern.