Single-sided triple layer optical disc
AssigneesKabushiki Kaisha Toshiba, Memory-Tech Corporation
InventorsToshihiro Sugaya, Masato Otsuka
Life of this patent
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Abstract
An optical disc is based on the following the distance of the light transmission layer from a light incidence plane to the first recording layer is a minimum of 550 μm. The distance between the first and the third recording layer is a maximum of 72 μm. The distance between the second and the third recording layer is a minimum of 15 μm. The distance between the first and the second recording layer is about 31 to 40 μm. The reflectivities of the first and the second recording layer with respect to the first laser beam are 18% or more, and the ratio between the reflectivities is about 1.15 or less. The areal recording density of the third recording layer is three times or more as high as the areal recording density of the first and the second recording layer.
Claims8
A single-sided triple layer optical disc comprising:
- a light transmission layer;
- a first recording layer and a second recording layer which are accessed with a first laser beam;
- and a third recording layer which is accessed with a second laser beam, these layers being arranged in that order in a direction in which the laser beams enter, wherein
- the distance of the light transmission layer from a light incidence plane to the first recording layer is a minimum of 550 μm,
- the distance between the first recording layer and the third recording layer is a maximum of 72 μm,
- the distance between the second recording layer and the third recording layer is a minimum of 15 μm,
- the distance between the first recording layer and the second recording layer is about 31 to 40 μm,
- the reflectivities of the first recording layer and the second recording layer with respect to the first laser beam are 18% or more, the ratio between the reflectivities being about 1.15 or less, and
- the areal recording density of the third recording layer is three times or more as high as the areal recording density of the first recording layer and the second recording layer.
An optical disc apparatus which reads information recorded on an optical disc,
- the optical disc being a single-sided triple layer optical disc comprising:
- a light transmission layer;
- a first recording layer and a second recording layer which are accessed with a first laser beam;
- and a third recording layer which is accessed with a second laser beam, these layers being arranged in that order in a direction in which the laser beams enter, wherein
- the distance of the light transmission layer from a light incidence plane to the first recording layer is a minimum of 550 μm,
- the distance between the first recording layer and the third recording layer is a maximum of 72 μm,
- the distance between the second recording layer and the third recording layer is a minimum of 15 μm,
- the distance between the first recording layer and the second recording layer is about 31 to 40 μm,
- the reflectivities of the first recording layer and the second recording layer with respect to the first laser beam are 18% or more, the ratio between the reflectivities being about 1.15 or less, and
- the areal recording density of the third recording layer is three times or more as high as the areal recording density of the first recording layer and the second recording layer,
- the information reading apparatus comprising:
- an optical head which is configured to generate the first laser beam and the second laser beam;
- and control means for causing the first laser beam or the second laser beam to be selectively generated.
An optical disc apparatus which reads information recorded on an optical disc,
- the optical disc being a single-sided triple layer optical disc comprising:
- a light transmission layer;
- a first recording layer and a second recording layer which are accessed with a first laser beam;
- and a third recording layer which is accessed with a second laser beam, these layers being arranged in that order in a direction in which the laser beams enter, wherein
- the distance of the light transmission layer from a light incidence plane to the first recording layer is a minimum of 550 μm,
- the distance between the first recording layer and the third recording layer is a maximum of 72 μm,
- the distance between the second recording layer and the third recording layer is a minimum of 15 μm,
- the areal recording density of the third recording layer is three times or more as high as the areal recording density of the first recording layer and the second recording layer,
- the distance between the first recording layer and the second recording layer is about 31 to 40 μm,
- the reflectivities of the first recording layer and the second recording layer with respect to the first laser beam are 18% or more, the ratio between the reflectivities being about 1.15 or less, and
- the reflectivity of the third recording layer with respect to the second laser beam is 14 to 28%,
- the information reading apparatus comprising:
- an optical head which is configured to generate the first laser beam and the second laser beam;
- and control means for causing the first laser beam or the second laser beam to be selectively generated.
Dependencies are inferred from the claim text.