Write-once-read-many optical disk having low-to-high recording property accommodating short wavelength recording
AssigneeRicoh Company, Ltd.
InventorNoboru Sasa
Life of this patent
Estimating the term…
Abstract
A write-only-read-many type optical recording medium includes a substrate, an organic material layer having a light absorption function that is sufficient for recording in the recording/reproduction wavelength range, the organic material layer being situated on the substrate, and a reflection layer being situated on the organic material layer. The recording medium is configured to have a Low-to-High recording property and record with a laser having a wavelength that is no greater than 500 nm.
Claims12
An optical recording medium exhibiting a Low-to-High recording property consisting essentially of:
- a substrate, an organic material layer, a heat insulating layer, a reflection layer, and a cover layer;
- wherein the organic material layer is provided on the substrate and has a thickness of 50 nm to 300 nm, and has a light absorption function that is sufficient for recording in the recording/reproduction wavelength range;
- wherein the reflection layer is provided on the organic material layer and has a thickness of from 50 nm to 300 nm;
- and
- wherein the heat insulating layer is provided between the organic material layer and the reflection layer and has a thickness of from 5 nm to 200 nm;
- wherein an unrecorded part of the optical recording medium is configured to exhibit a reflectivity that is lower than a reflectivity of a recorded part of the optical recording medium and wherein the recording/reproduction characteristics are obtained in a blue laser wavelength range operating at a wavelength range of no more than 500 nm;
- wherein the light absorption function of the organic material layer is provided solely by a material consisting of a single organic material having:
- a first absorption band situated toward a long wavelength side with respect to the recording/reproduction wavelength range,
- a second absorption band that does not belong to the first absorption band, the second absorption band situated in the vicinity of the recording/reproduction wavelength range, and
- a third absorption band situated toward a short wavelength side with respect to the recording/reproduction wavelength range, the third absorption band exhibiting an absorption greater than an absorption of the first absorption band, wherein the third absorption band has a largest absorption wavelength that is no greater than 300 nm,
- wherein the optical recording medium provides low-to-high recording at a recording power range of from 2 mW to 11 mW at a linear recording speed of 6 m/sec.
An optical recording medium exhibiting a Low-to-High recording property consisting essentially of:
- a substrate, a reflection layer, an organic material layer, a light absorption layer, and a cover layer;
- wherein the organic material layer is situated on the substrate and has a thickness of 50 nm to 300 nm, the organic material layer having a light absorption function that is sufficient for recording in a recording/reproduction wavelength range of no more than 500 nm;
- wherein the light absorption layer is situated adjacent to the organic material layer and has a thickness of 5 nm to 150 nm;
- wherein the reflection layer is provided on the organic material layer and has a thickness of from 50 nm to 300 nm;
- and
- wherein the organic material satisfies a relation of (light absorption function of organic material layer in recording/reproduction wavelength area)<(light absorption function of light absorption layer in recording/reproduction wavelength area);
- wherein an unrecorded part of the optical recording medium is configured to exhibit a reflectivity that is lower than a reflectivity of a recorded part of the optical recording medium;
- wherein the light absorption function of the organic material layer is provided solely by a material consisting of a single organic material having:
- a first absorption band situated toward a long wavelength side with respect to the recording/reproduction wavelength range,
- a second absorption band that does not belong to the first absorption band, the second absorption band situated in the vicinity of the recording/reproduction wavelength range, and
- a third absorption band situated toward a short wavelength side with respect to the recording/reproduction wavelength range, the third absorption band exhibiting an absorption greater than an absorption of the first absorption band, wherein the third absorption band has a largest absorption wavelength that is no greater than 300 nm,
- wherein the optical recording medium provides low-to-high recording at a recording power range of from 2 mW to 11 mW at a linear recording speed of 6 m/sec.
Dependencies are inferred from the claim text.