Abstract:
A multiple data layer optical disk drive system has fixed aberration correction and uses a disk with maximum interlayer spacing for reduced interlayer crosstalk. In one embodiment the multiple data layer disk has a substrate with a thickness that is reduced by approximately one-half the thickness of the spacer layer that separates the first and last data layers. The disk is designed to operate with a lens that has spherical aberration correction to compensate for the thickness of a conventional single data layer disk. This allows the disk drive to handle multiple data layer disks as well as to be backward compatible and thus handle conventional single data layer disks. The thickness of the substrate material plus one-half the thickness of the spacer layer material (which may have a different index of refraction than the substrate material) is equivalent, for purposes of spherical aberration correction, to the thickness of the substrate material used in the conventional single data layer disk. The focused spot with minimum spherical aberration is thus located at the middle of the spacer layer rather than on the first data layer. The spacer layer thickness is selected so that when the focused spot is located on either the first or last data layer there is some deliberately designed spherical aberration, although an amount that is acceptable. As a result the thickness of the spacer layer can be significantly increased to thereby reduce interlayer crosstalk. In another embodiment that substrate thickness and spacer layer thickness are selected and then the lens is corrected for spherical aberration corresponding to the thickness of substrate material plus one-half the thickness of spacer layer material.
Abstract:
PROBLEM TO BE SOLVED: To provide an optical data storage device provided with an optical disk drive mechanism and a plurality of data layer magneto-optical medium. SOLUTION: A magneto-optical medium is provided with a substrate 50, a first dielectric layer 130, a first magneto-optical data layer 132, a second dielectric layer 134, a transmitting member 78, a third dielectric layer 140, a second magneto-optical data layer 142, a fourth dielectric layer 144, and a reflection layer 146. The thickness of the magneto-optical layers and dielectric layer are selected so that magneto-optical reading of a signal received from the data layer is made optimum. A disk drive mechanism has a phase retarder improving the signal from the optical data layer. COPYRIGHT: (C)2004,JPO
Abstract:
PROBLEM TO BE SOLVED: To provide an optical data storage system with which data from any data layer of an optical medium consisting of a plurality of data layers is clearly read. SOLUTION: The optical data storage system suitable to a large capacity storage is composed of the optical medium having a multiple data surface and a driving device including an optical head. A desired data surface is irradiated with laser beams and reflected light is used as a signal by the driving device. When data in a deep data layer is read, since light has to pass through many layers, only a weak signal is obtained. Consequently, signal intensity is difference depending on the data surface. Respective data surface is optimized so that the signal intensity from each data surface becomes nearly equal by using the medium having a coated dielectric reflecting layer and by suitably selecting the coating material and its thickness. In the preferable embodiment, semiconductor material is stuck onto each data surface and the reflecting quantity is decided by the thickness. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
PROBLEM TO BE SOLVED: To provide an optical data storage system with which even data from any data layer of an optical medium consisting of plural data is clearly read. SOLUTION: The optical data storage system suitable to a large capacity of storage is composed of the optical medium having a multiple data surface and a driving device including an optical head. A desired data surface is irradiated with laser beams and reflected light is used as a signal by the driving device. When data in a deep data layer is read, since light has to pass through many layers, a weak signal only is obtained. Consequently, signal intensity is difference depending on the data surface. Respective data surface is optimized so that the signal intensity from each data surface becomes nearly equal by using the medium having a coated dielectric reflecting layer and by suitably selecting the coating material and its thickness. In the preferable embodiment, semiconductor material is stuck onto each data surface and the reflecting quantity is decided by the thickness.
Abstract:
PROBLEM TO BE SOLVED: To provide an optical data memory system which uses an optical medium having plural recording layers. SOLUTION: The substrate supports recording stacks 90, 92 of plural layers which are spatially separated, and the stacks contain recording layers 53, 64 comprising reversible or rewritable phase transition material in an active state. The recording stack 90 nearest to the substrate where laser light irradiates the surface 49 contains a reverse-writing type reversible phase transition material, namely a phase transition material which having an amorphous initiating phase in which recording is done by heating with a laser beam to change the data region into a crystalline phase. The first recording layer 53 is in contact with dielectric layers 51, 55. These dielectric layers have a higher refractive index than that of the adjacent recording layer and act as optical interference thin film so that these layers give an optical interference effect to enhance the light in the recording stack. These optical interference thin films do not absorb light so that the laser light can be focused on the recording layer in the recording stack 92.
Abstract:
An optical disk drive (10) uses an optical disk (12) with spatially separate d multiple phase-change WORM recording layers (51, 66). The optical disk has a light transmissive substrate onto which the laser light is incident. The substrate supports at least two spatially separated multi-film recording stacks (90, 92), each stack including an active recording layer of phase- change WORM material. The disk is either an air-gap (78) structure wherein each recording stack is supported on a separate substrate (50, 56) and the substrates (50, 56) are separated by an air-gap (78), or a solid structure wherein a solid light transmissive spacer layer (22) separates the recording stacks (90, 92). Each of the recording stacks (90, 92) located between the substrate (50) on which the laser light is incident and the farthest recordi ng stack includes an active phase-change recording layer (51) and an optical interference film (53) in contact with the recording layer (51). The recordi ng layer (51) is made sufficiently thin to have good light transmissivity, but at this low thickness, without any other layers, is not sufficiently reflective to act as a recording layer with suitable servo and recording performance. T he optical interference film (53) in contact with the recording layer (51) has a high index ofrefraction relative to the adjacent recording layer (51) and spacer (122) to increase the optical interference effect in the recording stack (90). The optical interference film (53) optimizes the contrast, reflectivity and transmissivitzy of the recording stack. The optical interference film (53) has low absoprtion so that laser light can pass throu gh it to focus on a farther recording layer (66). This allows the farther recording layers (66) to be written using reasonable laser power.
Abstract:
A magnetic disk with nonmagnetic information encoded under, in or above the magnetic layer of the disk is described along with the disk drive using the magnetic disks. The information may be stored as a series of laser-written marks (e.g., bumps, oxidized spots or spots with altered reflectivity) upon the surface(s) of each disk of the disk stack. The set of marks may be a series of laser bumps which serve a dual purpose as a landing zone or contact start/stop (CSS) zone for the slider and as encoded identifying information. During the manufacturing process for disk drives containing the disks, each disk's identifier can be read using outboard equipment such as an HRF tester or by means contained in the drive itself. Each disk identifier can then be stored magnetically in a special region of the hard disk reserved for use by the drive and/or within the flash memory of the hard drive. The drive can then communicate the identifier(s) to a host computer using the conventional communication hardware and firmware. In this way selected information such as the origin, batch number, date of manufacture, serial number, etc. of any disk can be obtained when needed as, for example, as part of failure analysis.
Abstract:
A multiple data layer optical disk drive system has fixed aberration correction and uses a disk with maximum interlayer spacing for reduced interlayer crosstalk. In one embodiment the multiple data layer disk has a substrate with a thickness that is reduced by approximately one-half the thickness of the spacer layer that separates the first and last data layers. The disk is designed to operate with a lens that has spherical aberration correction to compensate for the thickness of a conventional single data layer disk. This allows the disk drive to handle multiple data layer disks as well as to be backward compatible and thus handle conventional single data layer disks. The thickness of the substrate material plus one-half the thickness of the spacer layer material (which may have a different index of refraction than the substrate material) is equivalent, for purposes of spherical aberration correction, to the thickness of the substrate material used in the conventional single data layer disk. The focused spot with minimum spherical aberration is thus located at the middle of the spacer layer rather than on the first data layer. The spacer layer thickness is selected so that when the focused spot is located on either the first or last data layer there is some deliberately designed spherical aberration, although an amount that is acceptable. As a result the thickness of the spacer layer can be significantly increased to thereby reduce interlayer crosstalk. In another embodiment that substrate thickness and spacer layer thickness are selected and then the lens is corrected for spherical aberration corresponding to the thickness of substrate material plus one-half the thickness of spacer layer material.
Abstract:
An optical data storage system comprises a multiple data surface medium and optical head. The medium comprises a plurality of substrates separated by a light transmissive medium. Data surfaces are located on the substrate surfaces. A layer of a dye material is deposited onto each of the data surfaces. The thickness of the dye layer determines the amount of reflectivity for each of the data surfaces.