JPH07262605A - Optical disk - Google Patents

Abstract

PURPOSE:To obtain an optical disk suitable for decreasing the kinds of the optical disks to be prepd. in compliance with an optical disk reproducing device by providing the optical disk with at least two recordable and reproducible information recording regions where information is recorded with at different recording densities. CONSTITUTION:The magneto-optical disk 10 is a reloadable disk. The digital information is recordable and reproducible at the same recording density as the recording density of a CD-ROM in the recording and reproducing region 12. Recording at the 4-times density is possible in the high-density recording and reproducing region 14 on contrast with the ordinary density region. Recessed parts 16 for guiding form guide tracks for the purpose of recording and the pitch thereof is about 1.6mum. Guide recessed parts 18 of the high-density region 14 also form the guide tracks for recording and the pitch thereof is about 0.9mum. The ordinary region 12 and the high-density region 14 are formed of one kind of rare earth transition metal alloy films to cover the two recording wavelengths.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a read-only optical disk such as a CD-ROM and a recordable and playable optical disk such as a magneto-optical disk.

[0002]

2. Description of the Related Art Optronics, December 1, 1985
The maximum recording density that can be recorded on an optical disk is related to the oscillation wavelength of the semiconductor laser used for reproduction, as described in “Easy-to-understand optical disk” issued on 0th. If the wavelength is short, the recording density can be increased. It is possible.

That is, by using a short wavelength semiconductor laser, it is possible to reproduce a high density optical disc. Short-wavelength semiconductor lasers are being developed in sequence. Therefore, optical discs with various recording densities and optical disc reproducing apparatuses corresponding thereto can be considered.

The purpose of the present invention will be described. Optical discs on which program information is digitally recorded have been sold. In this way, when selling the program information, it is necessary to sell various types of optical discs according to the optical disc reproducing apparatus.

An object of the present invention is to provide an optical disc that prevents such a situation. Another object of the present invention will be described. 2. Description of the Related Art Conventionally, a partially writable optical disc called a partial ROM has been considered.

In the case of such a partially writable optical disc, it is not necessary to change the read-only area to the TV.
It is possible to write program information for a game or the like, write the progress and score of this TV game in a writable area, and temporarily save. To increase the capacity of information recorded on such an optical disc, as described above,
Reproduction may be performed by a short wavelength laser using an optical disc recorded at high density.

By the way, the output of the semiconductor laser required for recording is larger than the output of the semiconductor laser required for reproducing. For example, in a known magneto-optical disk called an MO disk, a laser output with a wavelength of 780 nm requires about 5 mW for reproduction and about 30 mW for recording. However, it is difficult to realize stable oscillation of a short wavelength semiconductor laser with high output. Therefore, in a writable high-density optical disc, a high-power short-wavelength semiconductor laser is required to write information in a writable area, which is difficult to realize.

However, since the recording density of the recordable magneto-optical disk is the conventional recording density, the amount of information is limited. Another object of the present invention is to provide an optical disk which has a large amount of recorded information and which can be recorded without using a high output short wavelength semiconductor laser.

[0009]

As described above, an object of the present invention is to provide an optical disc adapted to reduce the number of optical discs that must be prepared for an optical disc reproducing apparatus when writing program information. To do. Another object of the present invention is to provide an optical disk which has a large amount of recorded information and which can be recorded without using a high output short wavelength semiconductor laser.

[0010]

The optical disc of the present invention comprises:
It is characterized by having at least two information recording areas for recording information at different recording densities. The optical disk of the present invention is a magneto-optical disk having at least two information recording areas for recording information at different recording densities.

The optical disk of the present invention is characterized in that it has at least two information recording areas for recording information at different recording densities and records this information as pits. The optical disc of the present invention is characterized by having at least two recordable and reproducible information recording areas for recording information at different recording densities.

The optical disc of the present invention is a magneto-optical disc having at least two recordable and reproducible information recording areas for recording information at different recording densities. The optical disc of the present invention is characterized by having at least two read-only information recording areas for recording information at different recording densities. The optical disc of the present invention is characterized by having at least two read-only information recording areas for recording information at different recording densities, and recording this information as pits.

The optical disk of the present invention has at least two information recording areas for recording information at different recording densities, and one of the two information recording areas is a recordable / reproducible area and the other is reproducible. It is a special area. The optical disc of the present invention comprises at least two information recording areas for recording information at different recording densities,
Further, of the two information recording areas, an area having a low recording density is a recordable / reproducible area, and the rest is a reproduction-only area.

The optical disk of the present invention is characterized in that the same program information is recorded in at least two areas having different recording densities. The optical disc of the present invention is characterized by having at least two information recording areas for recording information at different recording densities, and recording the same information in these two information recording areas.

[0015]

According to the present invention, the optical disk has at least two information recording areas for recording information with different recording densities. Further, according to the present invention, the recording density of the recording / reproducing area of the optical disc is lower than the recording density of the reproduction-only area.

Further, according to the present invention, the same information is recorded in at least two areas having different recording densities on the optical disc.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, (10) is a magneto-optical disk. That is, it is a rewritable optical disc.
Reference numeral (12) is a recording / reproducing area of this magneto-optical disk, in which digital information can be recorded / reproduced at the same recording density as a conventional CD-ROM or the like. In this embodiment, this region (12) will be referred to as a normal density region hereinafter.

Reference numeral (14) is a high-density recording / reproducing area of this magneto-optical disk, which enables recording at a density of about 4 times. Hereinafter, this region (14) will be referred to as a high density region. FIG. 2 is a sectional view of the normal density region (12).
(16) is a guide recess for forming a guide track for recording. The pitch of this track is about 1.6 μm
Is. For this normal density region (12), a 780 nm laser is used as in a CD-ROM.

FIG. 3 is a cross-sectional view of the high density region (14). (18) is a guide recess for forming a guide track for recording. The pitch of this track is about 0.9
μm. A 635 nm laser is used for this high density region (14). The normal density region (12) and the high density region (14) are made of one kind of rare earth transition metal alloy film that covers two recording wavelengths.

Further, in the magneto-optical disk (10) of this example, the guide track has been described as the concave portion, but the convex portion may be used as the guide track. The magnetic domain in which information is recorded (magnetized) is formed in this concave portion and / or convex portion. The writing operation to this magneto-optical disk will be described. The same program information is written and sold by the distributor on the normal density area (12) and the high density area (14) of the optical disk (10) such as a magneto-optical disk.

As is well known, in the MD format and the like, the optical disc is reproduced from the inner circumference side. Further, here, since the normal density area (12) is provided on the inner peripheral side, reproduction can be performed even in the conventional disc reproducing / recording apparatus. It should be noted that the reproduction device dedicated to the high density disc is configured to normally read the program information of the high density region (14) on the outer peripheral side even if the normal density region (12) is provided on the inner peripheral side. For example, the reproduction may be performed from the outer peripheral side.

Although the rewritable magneto-optical disk has been described in the above embodiments, an optical disk for recording information in pits (an optical disk in a narrow sense, a CD
-A read-only optical disk such as ROM or CD-I)
An example applied to will be described. In FIG. 4, (20) is
This is a read-only optical disc. (22) is a normal recording area in which digital information is conventionally recorded at a recording density.

Reference numeral (24) is a high-density recording area of this optical disk, which is recorded at a density of about 4 times. Figure 5
It is a sectional view of a normal recording area (22). (26) is a pit in which information is recorded. The pits are arranged in a spiral shape, and the pit row arranged in the spiral shape also guides the laser beam during reproduction.

FIG. 6 is a cross-sectional view of the high density region (24). (28) is a pit in which information is recorded.
The pits are arranged in a spiral shape, and the pit row arranged in the spiral shape also guides the laser beam during reproduction. In addition,
When reproducing the normal density area (22) and the high density area (24), the reproduction accuracy is improved by changing the wavelength of the laser used, but this is not an essential condition.

Next, an example of use of the optical disc (10, 20) will be described. The same TV game program information is recorded in each area of the optical disc (10, 20). In this way, the same information can be recorded in 1 at different recording densities.
It is possible to record on one optical disk. Next, a usage example of an optical disc having a writable area will be described.

For example, in the above-mentioned optical disc (10), the distributor writes the program information for the TV game in the high-density area (14). Then, the user attaches the optical disk (10) to the optical disk recording / reproducing apparatus for TV game and plays. Normal density area (12) is for this TV
It is used as an area for writing scores and progress in the middle of the game. The use of this normal density area (12) as an area for writing the midpoint score and the midway progress is defined by the program information for the TV game recorded in the high density area (14) in advance.

As described above, since the program is recorded in the high density area (14), the amount of recorded information can be increased. Moreover, since the normal density area (12) is a writable recording area, writing can be performed by using a laser having a normal wavelength. By the way, as described above, the normal recording density area of the optical disc of this embodiment is set on the inner circumference side of the optical disc. This has the effect of facilitating compatibility with conventional read-only optical disks.

Although the optical disk of this embodiment has the normal density area on the inner circumference side and the high density area on the outer circumference side, the present invention may be reversed. Further, although one each of the two types of density regions is provided, the present application is not limited to this. Further, the present application may provide three types of density regions. The optical disc of the present embodiment is composed of tracks (18,
The track pitch of the guide tracks (16, 26) in the normal density recording area is larger than the track pitch of 28).

The optical disc for recording the same program in two areas may be a magneto-optical disc or a read-only optical disc. In short, the program software information for starting the same game may be stored in the areas recorded with different recording densities. In the above description, all the optical discs for writing the program information for the TV game are set as the recording / reproducing area as one magneto-optical disc (10). Is a read-only area in which information is recorded by the normal density area (1
2) may be a recordable / rewritable (writable) magneto-optical medium area. The point is that the recording / reproducing area may be a low-density area.

Further, in the above description, the writable recording / reproducing area is composed of a magneto-optical medium and is a writable area (rewritable area). However, in the present application, separately, the writable recording / reproducing area may be a writable area only once. In other words, this recording / reproducing area is recorded in the conventionally known write-once optical disc (CD-
It may be configured similarly to R).

The writable recording / reproducing area may be of the phase change type instead of the magneto-optical rewriting type. Regarding such a phase change (transition) and the like, especially on page 105 of the “easy-to-understand optical disc” and “Image Information Engineering and Broadcasting Technology, 1990” by the Institute of Television Engineers of Japan, 1990.
No. 0, Special Thesis: Optical Disc ", pages 76 to 83, etc., and is well known to those skilled in the art.

Further, in this embodiment, the density of the areas (12, 22) recorded at the normal density is set to the conventional CD-ROM.
Area of high density recording (14, 2)
Although the density in 4) has been described as being four times as high as this, the present application is not limited to this.

[0033]

Since the optical disk of the present invention has at least two areas having different recording densities, one optical disk having different recording density areas can be realized. Further, since the optical disk of the present invention has at least two areas having different recording densities, the same program can be written in this area.

Further, in the optical disc of the present invention, the same program information is recorded in at least two areas having different recording densities, so that the program information of different recording densities can be recorded in one optical disc. Further, in the optical disc of the present invention, since the recording area having a low recording density is used as the writable recording / reproducing area, it is possible to provide an optical disc which has a large amount of recorded information and can be easily recorded.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention.

FIG. 2 is a partially cutaway sectional view of the inner peripheral side of the magneto-optical disk of the first embodiment.

FIG. 3 is a partially cutaway sectional view of the outer peripheral side of the magneto-optical disk of the first embodiment.

FIG. 4 is a diagram illustrating a second embodiment of the present invention.

FIG. 5 is a partially cutaway sectional view of the inner circumference side of the optical disc of the second embodiment.

FIG. 6 is a partially cutaway sectional view of an outer peripheral side of the optical disc in the second embodiment.

[Explanation of symbols]

 (10) Magneto-optical disk (optical disk), (12) Recording / reproducing area (normal density area), (14) Recording / reproducing area (high density area), (16, 18) Recess (guide track), (20) Optical disk, (22) Play-only area (normal density area), (24) Play-only area (high density area), (26, 28) pits (rows form guide tracks).

Claims (10)

[Claims] 1. An optical disc having at least two information recording areas for recording information at different recording densities. 2. The optical disc according to claim 1, wherein the optical disc is a magneto-optical disc. 3. The optical disc according to claim 1, wherein information is recorded as pits on the optical disc. 4. The optical disc according to claim 1, wherein the two information recording areas are recordable and reproducible areas. 5. The optical disc according to claim 1, wherein the two information recording areas are reproduction-only areas. 6. The optical disc according to claim 1, wherein one of the two information recording areas is a recordable / reproducible area and the other is a reproduction-only area. 7. The optical disc according to claim 6, wherein an area having a low recording density of the two information recording areas is a recordable and reproducible area. 8. The optical disc according to claim 4, wherein the recordable and reproducible area is a rewritable area. 9. The optical disc according to claim 4, wherein the recordable and reproducible area is a one-time writable area. 10. The optical disc according to claim 1, wherein the same information is recorded in the two information recording areas.