JPH0453011B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to the configuration of an information track of a disk-shaped record carrier (hereinafter referred to as a disk) for optically recording and reproducing images, audio, digital data, etc. In particular, the present invention relates to the structure of a recordable disc having a guide track (hereinafter abbreviated as pre-group) and an address signal provided together with the pre-group.

Prior Art FIG. 5 shows an example of the structure of a conventionally used recordable disc. In FIG. 5, 1 is a disk, 2 is a pregroove, and 3 to 6 are address signals provided one per round of the pregroove, indicating the address of the pregroove. FIG. 5 also shows an enlarged view of the address signal, in which the address signal is constructed by intermittent pregroove 2.

Pregroove 2 and address signals 3 to 6 are generally provided at a pitch of about 1.6 microns,
The width is approximately 0.7 microns, and the height is approximately 0.08 microns, which are configured as minute protrusions or depressions.

FIG. 6 is an enlarged view of the signal pits recorded in the pregroove and the address signal pits. By irradiating pregroove 2 with a laser beam modulated by the signal to be recorded,
A recorded signal pit 11 is obtained. This signal pit is recorded, for example, as a change in the reflectance of the recording layer provided in the pregroove 2. On the other hand, address signals 3 to 6 are constructed by intermittent pregroove 2. A reproduction laser spot for reproducing the recorded signal pits and address signal pits is shown at 12.

As another conventional example, as shown in Japanese Patent Application No. 59-185503, a method has been proposed in which address sections are arranged in a staggered manner in order to reduce crosstalk between adjacent address sections. An example of this configuration is shown in FIG. In Fig. 7, pregroove P ₁ is section 3.
0 has an address signal pit 32 in the address section 31, and the next pregroove _P2 has an address signal pit in the address section 34 of the section 31. Hereinafter, as shown in the figure, the address signal 33 of the next pregroove P ₃ is set in section 30, and the address signal 35 of pregroove P ₄ is set in section 31, so that the address signals are not adjacent to each other.

Problems to be Solved by the Invention However, in recent years, there has been a demand for higher S/N of recorded and reproduced images for these conventional disk configurations.
It is now necessary to increase the amount of light reflected from the pregroove.

In order to increase the amount of light reflected from the pregroove, it is necessary to reduce the diffraction loss due to the pregroove at the reproduction spot.

FIG. 8 shows the relationship between the amount of reflected light and the pregroove line width. As is clear from FIG. 8, in order to increase the amount of light reflected from the pregroove, it is necessary to make the pregroove width wider or narrower with respect to the pitch.

When recording between pregrooves without recording on the pregrooves, the reflectance is 100%, but
When considering compatibility with conventional disks, there are problems such as the need to switch the tracking polarity.

Figures 9a, b, and c show reflectance changes when the conventional pregroove width and address pit width are approximately equal, and reflectance changes when the address pit width is the same as before and the pregroove width is narrowed and widened.
Shown below. A shows the case where the pregroove width and the address signal pit width are equal, and the reflectivity of the pregroove and address signal pit portions is equal, and the reflectance is higher in the land portion between the pregroove and the address pit, and the address signal reproduction is difficult. There is no problem in detection. b and c are the cases where the pit width of the address signal is the same as the conventional one, but the pregroove width is narrower or wider. In this example, b, c
This shows the case where the reflectance from the pregroove is equal. In this case, the problem is that the reflectance of the pre-groove and the reflectance of the address pit are different between the first pit and the last pit of the address pit, and the reflectance of the pre-groove is high, making it impossible to detect address signal playback. It has points.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention aims to provide a method for configuring an optical disk that increases the reflectance of the pregroove and does not cause problems in address signal reproduction detection.

Means for Solving the Problems In order to solve the above problems, the configuration of the optical disk of the present invention is such that the reflectance is approximately equal to the pit width of the address signal over a desired section before and after the address signal section. The first and second sub-guide tracks (sub-pregroove portions) are provided.

Effect: With the above-described configuration, the reflectance of the sub-pregroove portion and the address pit portion are equalized over the desired section, eliminating problems in address signal reproduction detection and accurately performing reproduction detection in step 5. be able to.

Example FIG. 1 shows an example of the configuration of the present invention.

Between the address section 6 of the pregroove section 2, a sub-pregroove section 42 is provided as a desired section before and after the address section 6. This secondary pre-groove 42
The width of the address pit is approximately equal to the width of the address pit.

For this reason, the reflectance of the sub-pregroove 42 and the address pit section become equal, and as shown in the reflectance change shown in Fig. 2, the address signal reproduction can be detected normally even at the first pit and the last pit of the address pit section. becomes.

The sub-pregroove section before the address section should be set to a desired value depending on the rotation speed of the optical disk, the disk diameter, etc., as well as the time constant of the clamp circuit of the address detection system, and should be set to a desired value of several microseconds to
It is about 100 microseconds.

However, the sub-pregroove section after the address section only needs to detect the final pit of the address section normally, and is preferably shorter than the second groove section before the address section.

Also, depending on how the pregroove width and address width are selected, as shown in Figure 3, the reflectance changes suddenly at the boundary between the first and second sub-pregrooves, causing the playback level to change at the output of the signal detection circuit. It has been confirmed through experiments that the

Another embodiment of the present invention for solving such problems is shown in FIG.

Between the pregroove section 2 and the address section 6, a first sub-pregroove section 42 and a second sub-pregroove section 44 are provided in desired sections before and after the address section 6. The above-mentioned problem can be solved by configuring the width of the second sub-pregroove and the width of the first sub-pregroove to change substantially continuously.

Although the embodiments of the present invention have been explained using embodiments having different groove widths, the reflectance of the pregroove also changes depending on the phase difference. Also, the reflectance of the recording medium changes depending on the reflectance of the recording degree,
The present invention is intended to include all such methods as long as the same effects as those of the present invention can be obtained.

Effects of the Invention As described above, according to the present invention, an optical disc having a configuration in which the pregroove width is narrowed or widened in order to increase the reflectance of the pregroove is compatible with the conventional address reproduction signal output. While doing so,
Moreover, it is possible to obtain an optical disc that does not cause problems in detecting address reproduction signals.

The present invention is applicable not only to address sections configured in a staggered manner, but also to optical discs configured such that the pregroove width and the address pit width are different. Regarding the second sub-pregroove, if the pregroove width and address pit width are approximately continuously changed,
It is applicable in any configuration.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the configuration of an information recording carrier in an embodiment of the present invention, FIG. 2 is a waveform diagram showing changes in reflectance, FIG. 3 is a waveform chart showing the reproduced signal waveform, and FIG. 4 5 is a plan view showing the structure of an information record carrier according to another embodiment of the present invention, FIG. 5 is a plan view showing the structure of a conventional information record carrier, FIG. Figure 7 is a plan view of another conventional disc, Figure 8 is a characteristic diagram showing the relationship between the groove width and reflectance, and Figure 9 is a diagram showing the relationship between the groove width and the reflectance, and Figure 9 shows the address pit width being constant and the pregroove width being varied. FIG. 4 is a plan view and a waveform diagram showing changes in reflectance in the case of FIG. 1...disc, 2...pregroove, 3~
6, 32-35...Address field, 11...Recorded information pit, 12...Reproduction laser spot, 42...First sub-pregroove, 44...Second sub-pregroove.

Claims (1)

[Scope of Claims] 1. An information recording carrier that stores predetermined information in an optically readable form, including a guide track, address, etc. that acts as a guide for recording optically readable information. an address pit portion having information of 1. An information recording carrier comprising first and second sub-guiding tracks having substantially the same reflectance as an address pit portion. 2. The information recording carrier according to claim 1, wherein the second sub-guide track section located after the address pit section is shorter than the first sub-guide track section located before the address pit section. 3. The information recording carrier according to claim 1 or 2, characterized in that the reflectance of the second sub-guide track section is changed almost continuously. 4. The information recording carrier according to claim 1, 2, or 3, characterized in that the guide track and the second sub-guide track are constructed in series.