Back to results
US 6,487,163 B1Granted
Optical disk and optical disk apparatus
AssigneeKabushiki Kaisha Toshiba
InventorsToshihiro Sugaya, Yoshinori Honguh
Life of this patent
Estimating the term…
Abstract
An optical disk comprising a substrate in which information to be picked up by a light beam radiated thereto through an objective lens are recorded as pit arrays formed at a predetermined track pitch, and a reflective layer formed on the substrate, the track pitch is set within a range of (0.72 to 0.8)α×(λ/NA)/1.14 μm, when a wavelength of the light beam is λnm and the objective lens has a numerical aperture of NA, the α is represented by: α=3.617×10−14×(θA ds/λ)3+1.248×10−9×(θA ds/λ)2+0.865 when a thickness of the optical disk is ds μm, and an allowable tilt angle of θA, and the allowable tilt angle θA is not more than 7 mrad.
Claims16
An optical disk comprising:
- a substrate in which information to be picked up by a light beam radiated thereto through an objective lens are recorded as pit arrays formed at a predetermined track pitch;
- and a reflective layer formed on the substrate,
- wherein the track pitch is set within a range of
- (0.72 to 0.8)α×(λ/NA)/1.14 μm,
- when a wavelength of the light beam is λμm and a numerical aperture of the objective lens is NA,
- the α is represented by:
- α=3.617×10−14×(θA ds/λ)3+1.248×10−9×(θA ds/λ)2+0.865
- when a thickness of the optical disk is ds μm, and an allowable tilt angle of the optical disk is θA mrad, and
- the allowable tilt angle θA is not more than 7 mrad.
6 more elements
An optical disk apparatus comprising:
- an optical disk including a substrate in which information are recorded as pit arrays formed at a predetermined track pitch, and a reflective layer formed on the substrate;
- an objective lens arranged to face the optical disk;
- a light beam generator which radiates a light beam onto the optical disk through the objective lens;
- and a reproduction unit which detects a reflected beam of the light beam radiated onto the optical disk by the light beam generator so as to reproduce the information recorded in the optical disk,
- wherein the track pitch is set within a range of
- (0.72 to 0.8)α×(λ/NA)/1.14 μm,
- when a wavelength of the light beam is λμm and a numerical aperture of the objective lens is NA,
- the α is represented by:
- α=3.617×10−14×(θA ds/λ)3+1.248×10−9×(θA ds/λ)2+0.865
- when a thickness of the optical disk is ds μm, and an allowable tilt angle of the optical disk is θA mrad, and
- the allowable tilt angle θA is not more than 7 mrad.
8 more elements
An optical disk comprising:
- a substrate in which information to be reproduced in response to a light beam radiated thereto through an objective lens are recorded as pit arrays formed at a predetermined track pitch;
- and a reflective layer formed on the substrate,
- wherein the track pitch is set within a range of
- (0.72 to 0.8)α×(λ/NA)/1.14 μm,
- when a wavelength of the light beam is λμm and a numerical aperture of the objective lens is NA,
- each of pits of the pit arrays is a trapezoidal-section pit which has an upper-region width within a range of
- (0.3 to 0.50)α×(λ/NA)/1.14 μm
- and a lower-region width within a range of
- (0.2 to 0.32)α×(λ/NA)/1.14 μm,
- and
- the α is represented by:
- α=3.617×10−14×(θA ds/λ)3+1.248×10−9×(θA ds/λ)2+0.865
- when a thickness of the optical disk is ds μm, and an allowable tilt angle of the optical disk is θA mrad.
10 more elements
An optical disk apparatus comprising:
- an optical disk including a substrate in which information are recorded as pit arrays formed at a predetermined track pitch, and a reflective layer formed on the substrate;
- an objective lens arranged to face the optical disk;
- means for radiating a light beam onto the optical disk through the objective lens;
- and means for detecting a reflected beam of the light beam radiated onto the optical disk by the radiating means so as to reproduce the information recorded in the optical disk,
- wherein the track pitch is set within a range of
- (0.72 to 0.8)α×(λ/NA)/1.14 μm,
- when a wavelength of the light beam is λμm and a numerical aperture of the objective lens is NA,
- each of pits of the pit arrays is a trapezoidal-section pit which has an upper-region width within a range of
- (0.3 to 0.50)α×(λ/NA)/1.14 μm
- and a lower-region width within a range of
- (0.2 to 0.32)α×(λ/NA)/1.14 μm,
- and
- the α is represented by:
- α=3.617×10−14×(θA ds/λ)3+1.248×10−9×(θA ds/λ)2+0.865
- when a thickness of the optical disk is ds μm, and an allowable tilt angle of the optical disk is θA mrad.
12 more elements
An optical disk comprising:
- a substrate in which information to be reproduced in response to a light beam radiated thereto through an objective lens are recorded as pit arrays formed at a predetermined track pitch;
- and a reflective layer formed on the substrate,
- wherein the track pitch is set within a range of
- (0.72 to 0.8)α×(λ/NA)/1.14 μm,
- when a wavelength of the light beam is λμm and a numerical aperture of the objective lens is NA,
- each of pits of the pit arrays is a trapezoidal-section pit which has an upper-region width within a range of
- (0.3 to 0.50)×(λ/NA)/1.14 μm
- and a lower-region width within a range of
- (0.2 to 0.32)×(λ/NA)/1.14 μm,
- and
- the α is represented by:
- α=3.617×10−14×(θA ds/λ)3+1.248×10−9×(θA ds/λ)2+0.865
- when a thickness of the optical disk is ds μm, and an allowable tilt angle of the optical disk is θA mrad.
10 more elements
An optical disk apparatus comprising:
- an optical disk including a substrate in which information are recorded as pit arrays formed at a predetermined track pitch, and a reflective layer formed on the substrate;
- an objective lens arranged to face the optical disk;
- a light beam generator which radiates a light beam onto the optical disk through the objective lens;
- and a reproduction head which detects a reflected beam of the light beam radiated onto the optical disk by the light beam generator so as to reproduce the information recorded in the optical disk,
- wherein the track pitch is set within a range of
- (0.72 to 0.8)α×(λ/NA)/1.14 μm,
- when a wavelength of the light beam is λμm and a numerical aperture of the objective lens is NA,
- each of pits of the pit arrays is a trapezoidal-section pit which has an upper-region width within a range of
- (0.3 to 0.50)×(λ/NA)/1.14 μm
- and a lower-region width within a range of
- (0.2 to 0.32)×(λ/NA)/1.14 μm,
- and
- the α is represented by:
- α=3.617×10−14×(θA ds/λ)3+1.248×10−9×(θA ds/λ)2+0.865
- when a thickness of the optical disk is ds μm, and an allowable tilt angle of the optical disk is θA mrad.
12 more elements
Dependencies are inferred from the claim text.