The present invention relates to a method of manufacturing an optical disc and optical disc apparatus and can be applied, for example, to a phase changing type of optical disc. The present invention can reliably detect addresses recorded in an optical disc by effectively utilizing an information recording surface even when data is recorded at high density. Address data, such as position information, is recorded to an optical disc using a spiral groove formed as a laser beam guide groove.
In an optical disc apparatus for recording information of high recording density, the desired data is recorded in sectors with reference to the address data recorded previously to an optical disc by a pre-pit.
Namely, an optical disc of this type forms sectors by dividing the information recording surface using a predetermined angular interval. In each sector, a sector address is recorded by a pre-pit at a starting area, and the subsequent area is assigned to a user area.
An optical disc apparatus obtains blocks from user data which are sequentially input in units of 2048 bytes and records the blocks in the user area of each sector with reference to the sector addresses recorded in the optical disc.
As an optical disc apparatus of this type, a DVD (Digital Versatile Disc) has been proposed. In the DVD, a laser beam having wavelength of 650 [nm] is irradiated to an optical disc through an optical system having a numerical aperture 0.6 to record the data of 2.6 [MB] at a single surface. In such DVD, a video signal can be recorded for about an hour with the single surface.
Meanwhile, in a home video tape recorder, the basic recording time is two hours. Moreover, a video signal recorded for about three hours should support an editing operation, etc. by effectively utilizing the random access function of an optical disc. With reference to the DVD system in this case, it is required to accommodate the data of about 8 [MB] for recording.
The recording density of the optical disk of this type can further be improved by accessing the optical disc using the optical system of higher numerical aperture. In this case, an optical disk is formed by setting thickness, for example, of an optical transmitting layer to about 1 [mm] by lowering the allowable skew margin of the optical disk apparatus.
However, when thickness of the optical transmitting layer is set to about 0.1 [mm], it becomes difficult to correctly reproduce sector address and user data because of dust adhered to the disk surface. In this case, to reduce the harmful effect of dust, etc., error correction capability may be enhanced for user data. However, in regard to sector address, when error correction capability is increased, capacity for the user area is greatly reduced, and it also becomes difficult to effectively use the information recording surface.
USPTO Backgrounds
USPTO Backgrounds