JPH03266236A - Information recording medium - Google Patents

Abstract

PURPOSE:To obtain almost same levels of tracking error signals by providing guide grooves in a manner that width of the guide groove in an information recording area is different from that of the guide groove in an information reproducing only area. CONSTITUTION:The medium has two areas of an area 6 for information reproducing only and an area 5 in which information can be written, and the medium has such a structure including guide grooves 1 in the information recording area 5 and guide grooves 3 containing pits 4 in the reproducing only area 6 formed on one substrate. The guide grooves are provided in a manner that width W2 of the guide groove 1 in the information recording area 5 is different from width W1 of the guide groove 3 in the information reproducing only area 6. By this method, both of the tracking error signal V2 in the recording area and the tracking error signal V1 in the reproducing-only area having pits are made in almost same levels.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information recording medium for optically recording, reproducing, and erasing information.

[Prior Art] Information recording media that optically record, reproduce, and erase information use the interaction between light and optical recording materials to write and reproduce information, and are generally well known as optical disks. .

Conventionally, information recording media have been of the read-only type, write-once type,
Rewritable types have been put into practical use, and media in which a read-only area and a recordable area are formed on the same medium are being developed.

By the way, when used as a storage device for a computer or the like, if a reproduction-only area and a recordable area are formed on the same medium, for example, a word processor system program is stored in the reproduction area, a document file is provided in the recording area, and so on. It becomes possible to store the system and documents on a single disk. In a medium having two areas, when a guide groove for an information recording area and a guide groove for an information reproduction exclusive area having a pit structure are formed on the same substrate,
The groove width of the guide groove in the information recording area and the groove width of the guide groove in the information reproduction exclusive area are structured to be the same.

The above-mentioned prior art will be explained with reference to the drawings. Figure 5 shows the same
This figure shows a conventional information recording medium having a read-only area and a recordable area on the medium. In other words, in FIG. 5, 1 is the groove in the information recording area, 2 is the gap between the grooves in the information recording area, and 3 is the groove in the information recording area.
4 is a groove in the reproduction-only area, and 4 is a pit.

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

A medium having two areas consisting of an information reproducing area 6 and an information recordable area 5 has a guide groove 1 for the information recording area 5 and an information reproducing area 6 having a pit 4 structure on the same substrate.
A guide groove 3 is formed, and the relationship between the groove width W2 of the guide groove 1 of the information recording area 5 and the groove width W1 of the guide groove 3 of the information reproduction exclusive area 6 is substantially such that W2 = W+. was.

[Problems to be Solved by the Invention] However, if the groove width of the guide groove in the information recording area and the groove width of the guide groove in the information reproduction-only area are the same, it is difficult to record, reproduce, or erase information between the grooves. , when focusing is applied between the grooves, the tracking error signal becomes small in the information reproduction exclusive area having a pit structure, which poses a problem that gain control becomes necessary. That is, as shown in FIG. 6, the tracking error signal V2 of the information recording area 6 is smaller than the tracking error signal V2 of the information recording area 6, and as a result, gain control becomes necessary.

In order to solve the problems of the prior art, the present invention provides an information recording medium that can make the tracking error signal of the information recording area and the tracking error signal of the information reproduction exclusive area having a pit structure almost equal in magnitude. With the goal.

[Means for Solving the Problems] In order to achieve the above object, the information recording medium of the present invention has a guide groove for an information recording area and a guide groove for an information reproduction exclusive area having a pit structure formed on the same substrate. An information recording medium for optically recording and erasing information, characterized in that the groove width of the guide groove in the information recording area and the groove width of the guide groove in the information reproduction exclusive area are formed to be different. .

In the above configuration of the present invention, the guide grooves are arranged so that the relationship W2 < Wl < 2W2 holds, where Wl is the groove width of the guide groove in the information reproduction only area, and W2 is the groove width of the guide groove in the information recording area. It is even more preferable to form.

[Function] According to the configuration of the present invention described above, since the groove width of the guide groove in the information recording area and the groove width of the guide groove in the information reproduction exclusive area are formed to be different, the tracking error signal of the information recording area is It is possible to realize an information recording medium in which the tracking error signals of the information reproduction exclusive area having the pit structure and the pit structure can be made to have approximately the same magnitude.

[Example 1] An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a cutaway cross-sectional view of an information recording medium in an embodiment of the present invention. In FIG. 1, 1 is a groove in an information recording area, 2 is a gap between grooves in an information recording area, 3 is a groove in a read-only area, 4 is a pit, 5 is an information recording area, and 6 is an information read-only area.

The operation of the information recording medium according to the embodiment of the present invention having the above structure will be explained below.

A medium having two areas consisting of an information reproducing area 6 and an information recordable area 5 has a guide groove 1 for the information recording area 5 and an information reproducing area 6 having a pit 4 structure on the same substrate.
A guide groove 3 is formed. The groove width W2 of the guide groove 1 of the information recording area 5 and the information reproduction exclusive area 6
The guide grooves 3 are formed with different groove widths W1.

By doing this, as shown in FIG. 2, the tracking error signal (2) of the information recording area and the tracking error signal (2) of the information reproduction exclusive area having a pit structure can be made to have approximately the same magnitude.

Next, FIG. 4 shows the relationship between groove width and tracking push-pull signal modulation degree. This is the tracking push-pull signal modulation degree when the track pitch is, for example, 1.6 μm. In FIG. 4, if the reflectance of the mirror surface of the information recording medium is IO, and the push-pull signal is IPP, then the tracking push-pull signal modulation degree is I,...
/IO, and in the groove width range of 0 to 0.8 μm, the tracking push-pull signal modulation degree increases monotonically with respect to the groove width, and when the groove width is 0. It can be seen that the maximum value is reached at 8 μm. Therefore, in order to increase the tracking error signal, it is better to widen the groove width. For example, the groove width W2 of the information recording area is IPP/IO
= 0. It is good to set the groove width W2 of the information recording area to 0.4 to 0.65.
．． 5 μm was optimal.

On the other hand, in the information recording and reproducing area, the depth is 1 in advance.
Approximately 300 zero pits are formed, and if a guide groove is formed with the same width as the groove width of the information recording area, the tracking error signal will become smaller as shown in FIG.
Widen the groove width and make the tiger 1. An attempt was made to increase the King error signal. As shown in FIG. 3, an information reproduction exclusive area was formed on the inner circumferential side of the substrate, and an information recording area was formed on the outer circumferential side of the substrate. In this case, the guide groove is formed so that the relationship W2 < Wl < 2W2 is established between the groove width W2 of the information recording area and the groove width W1 of the information reproduction area, and the information recording medium as shown in FIG. It was created. The groove width W of the information reproduction exclusive area is set to a range that provides a tracking push-pull signal modulation degree of about 0.7 to 0.8 from FIG.
= Q, 7 μm, W2 = 0°5 μm. By widening the groove width, the distance between the grooves where the pits are formed becomes narrower, but in order to maximize the modulation degree of the pits,
By setting the depth (d=λ/4), sufficient signal contrast can be obtained. As a result, even if the grooves become narrow, the C/N of the pits does not decrease.

If a width of W2=Wl=0.5 μm is formed as shown in FIG. 5, the tracking error signal V1 in the read-only area becomes clearly smaller as shown in FIG. 6, but the groove width in the information read-only area As shown in FIG. 2, it was confirmed that by widening the tracking error signal (2) in the information recording area and the tracking error signal (2) in the information reproduction only area, the tracking error signal (2) became equal.

As described above, according to this embodiment, by making the width of the guide groove of the information recording area wider than that of the information recording area, the information recording area and the information recording area can be placed on the same substrate. Even when the area is formed, an information recording medium is obtained in which the tracking error signal in the information recording area and the tracking error signal in the information recording area can be made to be approximately the same magnitude. As a result, the tracking servo can be made extremely stable, and gain control can be made unnecessary.

[Effects of the Invention] As explained above, in the present invention, the groove width of the guide groove in the information recording area and the groove width of the guide groove in the information reproduction-only area are formed to be different. To realize an information recording medium that can make the tracking error signal of the information recording area and the tracking error signal of the information reproduction exclusive area having a pit structure almost equal in magnitude even when a recording area and an information recording exclusive area are formed. A special effect can be achieved.

Further, in a preferred configuration of the present invention, when the groove width of the guide groove in the information reproduction only area is Wl and the groove width of the guide groove in the information recording area is W2, the guide is guided so that the relationship W2 < Wl < 2W2 holds. By forming the grooves, the tracking error signal in the information recording area and the tracking error signal in the information reproduction only area can be made more equal.

[Brief explanation of drawings]

FIG. 1 is a cutaway cross-sectional view of an information recording medium in an embodiment of the present invention, FIG. 2 is a diagram showing a tracking error signal of the information recording medium in FIG. 1, and FIG. 3 is a diagram showing a tracking error signal of the information recording medium in an embodiment of the present invention. FIG. 4 is a diagram showing the relationship between groove width and tracking push-pull signal modulation, FIG. 5 is a cutaway cross-sectional view of a conventional information recording medium, and FIG. It is a figure which shows the tracking error signal of the information recording medium of a figure. 1...Groove in information recording area, 2...Groove gap in information recording area, 3...Groove in playback-only area, 4...Picture recording area, 6...Information playback-only area. 5... Information Figure 3 Figure 4 1... Information recording area 2... Information recording area groove 3... Reproduction-only area 4... Bit 5... Information recording Area 6...Information reproduction only area 1...Full of information and edge area 2...Groove gap of information recording area 3...Groove 4 of reproduction only area...Pit 5...Information recording area 6 . . . Information reproduction exclusive area FIG. 1, FIG. 2, FIG. 5, and FIG. 6 W, <W.

Claims (2)

[Claims] (1) An information recording medium for optically recording and erasing information, in which a guide groove for an information recording area and a guide groove for an information read-only area having a pit structure are formed on the same substrate, wherein the information recording area is An information recording medium characterized in that the width of the guide groove and the width of the guide groove of the information reproduction exclusive area are formed to be different. (2) When the groove width of the guide groove in the information reproduction only area is W_1 and the groove width of the guide groove in the information recording area is W_2, W_2<
2. The information recording medium according to claim 1, wherein the guide groove is formed so that the following relationship holds: W_1<2W_2.