1. Field of the Invention
The present invention relates to an optical information recording medium being utilized for a recording and reproducing apparatus or a drive, which records an information in the optical information recording medium with moving the medium relatively and reads out the information from the medium, and a substrate and a manufacturing method for the optical information recording medium, particularly, relates to an optical information recording medium, which can be recorded and reproduced in a high density and a large capacity, and a substrate and a manufacturing method for the optical recording medium.
2. Description of the Related Art
Currently, there existed a system, which can optically record and reproduce information by using a disk shaped medium, as a system of an information recording medium for reading out information with moving the medium relatively. A disk system medium can be divided into several types such as a read only type or a ROM (read only memory) type, a recordable or a write once type or an “R” type and a rewritable type or a RW type. Generally, a recording density of a medium is high in a ROM type and low in “R” and RW types. For instance, in a DVD (digital versatile disk) system, which utilizes a laser beam having a wavelength of 635 through 650 nm, introduced into the market in 1996, a read only type disk such as a DVD-ROM disk and a DVD-Video disk was introduced first. A recording capacity of a read only type DVD disk is 4.7 GB. On the other hand, a recording capacity of a rewritable type DVD disk such as a DVD-RAM (DVD-Random Access Memory) disk is 2.6 GB, that is, the recording capacity of a DVD-RAM disk is almost 55% of that of a DVD-ROM disk. Researches and developments for increasing a recording capacity of a rewritable type disk are progressing. However, a system having a same capacity as that of a DVD-ROM disk has not been developed yet.
In the case of a rewritable type disk, a recording format on a disk and materials of recording medium are key technologies. In a DVD-RAM disk, a land-groove recording method, which is utilized for recording information on both land and groove of an optical information recording medium, has been used. In this method, an address necessary to recording and reproducing is recorded with cutting a land and a groove at each specific period of time.
FIG. 19 is a fragmentary plan view of a disk partially enlarging a microscopic construction 20, that is, a physical format construction of the land-groove recording method disk. In FIG. 19, the drawing shows an external appearance of the construction when the disk is not recorded and grooves 21a through 21c, hereinafter represented by the groove 21, are formed in parallel to each other. Lands 22a and 22b, hereinafter represented by the land 22, are allocated in between the grooves. An information is recorded on both the groove 21 and the land 22 when recording. A plurality of address pits 23a through 23n, which is necessary to recording and reproducing, is formed by cutting the groove 21 and land 22. The addresses occupy an area 24 in conjunction with an accompanied signal, so that the area 24 prevents a total capacity of a disk from increasing. In other words, a limited area of a disk can not be effectively utilized because of the area 24.
Further, with respect to recording material, in consideration of interchangeability with a read only type DVD disk drive, a phase change recording method, which does not utilize a magnetic head, is suitable. However, this method is defective in reflectivity, which is much inferior to a read only type disk or a write once type disk of utilizing dye. Accordingly, the low reflectivity results in that a recording capacity can not be increased.
By combining a microscopic construction or a physical format construction with a phase change material for high density recording and by optimizing them, a recording capacity equivalent to that of a read only type DVD disk can be realized.
An optical disk, which records addresses with scattering over a disk without having an inherent address area such as the area 24 shown in FIG. 19, is considered as a format for a large capacity optical disk. In other words, an address area such as the area 24 is not provided, so that a recording capacity can be increased as many as that of a DVD-ROM disk. However, in a case that a main recording signal is recorded in a vicinity area of an address signal, the main recording signal may interfere in the address signal and an error may occur by this method, and then rewriting can not be performed any more. Conversely, the address signal may leak into and interfere in the main recording signal and result in a reading out error.