OPTICAL DISC AND OPTICAL DISC DEVICE
First Claim
1. An optical disc comprising:
- a first recording layer, having a track upon which a first laser beam is focused; and
a management area and a user data area provided on said first recording layer, said management area having recorded information representing if a second recording layer upon which a second laser beam is focused is present in said optical disc and other recorded information representing if a third recording layer upon which a third laser beam is focused is present in said optical disc, and said management area being located interiorly to said user data area,wherein a wavelength of said second laser beam is longer than that of said first laser beam,wherein a wavelength of said third laser beam is longer than that of said second laser beam,wherein each of said information comprises two bits,wherein said information indicating said second recording layer represents absence of said second recording layer by bit values of 00 in a first position, andwherein said information indicating said third recording layer represents absence of said third recording layer by bit values of 00 in a second position.
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Abstract
In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.
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Citations
4 Claims
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1. An optical disc comprising:
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a first recording layer, having a track upon which a first laser beam is focused; and a management area and a user data area provided on said first recording layer, said management area having recorded information representing if a second recording layer upon which a second laser beam is focused is present in said optical disc and other recorded information representing if a third recording layer upon which a third laser beam is focused is present in said optical disc, and said management area being located interiorly to said user data area, wherein a wavelength of said second laser beam is longer than that of said first laser beam, wherein a wavelength of said third laser beam is longer than that of said second laser beam, wherein each of said information comprises two bits, wherein said information indicating said second recording layer represents absence of said second recording layer by bit values of 00 in a first position, and wherein said information indicating said third recording layer represents absence of said third recording layer by bit values of 00 in a second position. - View Dependent Claims (2, 3, 4)
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Specification