Fujitsu Corporation

Showa Denko K.k.

Toshiba Storage Device Corporation

Wataru Odajima

Shinya Hasegawa

Fumihiro Tawa

Nobuhide Aoyama

Shin-ya Hasegawa

A magnetic recording medium used for the thermally assisted magnetic recording system which fires a laser beam at a magnetic recording medium to partially heat the medium and applies a magnetic field from the outside to the part heated to lower the coercivity for recording. The magnetic recording medium is configured by a glass substrate on which a heat radiation layer, heat retention layer, intermediate layer, and recording layer are stacked. Further, the heat retention layer is configured by a member having an effective refractive index lower than the effective refractive index of the recording layer and having an temperature diffusion coefficient determined by the specific heat, density, and heat conductivity rate higher than glass and lower than metal. The material with a high temperature diffusion coefficient is used lowered in temperature diffusion coefficient using a porous structure or granular structure.

Magnetic recording medium for thermally assisted magnetic recording

An electromagnetic field simulator for repeatedly calculating a space distribution of an electromagnetic field at a next point in time using a distribution of an electromagnetic field in a 3-dimensional space includes: a unit for calculating a distribution of an electric field and a distribution of an magnetic field on the entire 3-dimensional space; a unit for calculating a distribution of an electric field and a distribution of an magnetic field on a 2-dimensional space on a cut plane obtained by cutting the 3-dimensional space by a plane; a unit for setting an excitation condition of generating an electromagnetic wave by using a calculation result of the 2-dimensional electromagnetic field calculating unit; and a unit for generating an electromagnetic wave by forcibly vibrating a part of the electric field and the magnetic field in the 3-dimensional space on a basis of the excitation condition set.

Electromagnetic field simulator and electromagnetic field simulating program product

An optical device includes a clad composed of a material having a first refractive index, a core which is embedded in the clad, composed of a material having a second refractive index different from the first refractive index, and tapers toward the end-point thereof, and a light-transmitting layer which is composed of a material different from the material having the second refractive index and cuts across an optical path at the end-point thereof.

Optical output device, magnetic storage medium drive unit, and head slider

The electromagnetic field simulator includes a discrete model setting section which sets a space grid width and a time step in a simulation of the electromagnetic field, a coefficient setting section which sets coefficients of equations for the simulation at various positions in a simulation space based on electromagnetic physical properties, a wave source setting section which sets a position and amplitude of a wave source of the electromagnetic wave as a boundary condition with respect to a spatial distribution of the electromagnetic field, and an amplitude calculation section which calculates amplitude of an electromagnetic field component given to the position of the wave source in the simulation space based on the space grid width and the time step and the electromagnetic physical properties at the position of the wave source to reproduce the electromagnetic wave having the set position and amplitude of the wave source in simulation results.

Electromagnetic field simulator and electromagnetic field simulation program storage medium

A wavelength computation unit computes a wavelength inside a substance based on the values of an analytical model that is set with an analytical model setting unit and values defining a wave source that is set by a wave source setting unit. A coefficients computation unit calculates the coefficients of a second computational formula for computing a polarization current when a grid spacing that is set by a computation conditions setting unit is equal to or larger than ' 1/10' of the wavelength inside the substance. When the grid spacing is less than ' 1/10' of the wavelength, the coefficients of a first computational formula is computed. A FDTD computation unit computes the first or second computational formula or each component of the electromagnetic field based on the FDTD method from the calculated coefficients.

Electromagnetic field simulator and electromagnetic field simulation program

An optical device and an information recording/reproducing apparatus using the optical device are disclosed. Incident light is output to a path selected from a plurality of paths so that an optical path can be secured with high precision for a separated (two-part) optical system. The optical device and the information recording/reproducing apparatus include a first reflective unit for reflecting the incident light in a fixed direction, and a second reflective unit for reflecting the light received from the first reflective unit to a second optical path. The two reflective units are movable in a body between two positions, one position being on a first optical path, and the other position being in an evacuation position where the first optical path is not intercepted.

Optical device, information recording/reproducing apparatus using the optical device

There is disclosed a small lightweight optical information storage apparatus which can obtain a sufficient writing light quantity, and an optical device which can realize the optical information storage apparatus. The optical device for use in the optical information storage apparatus has a splitting surface constituted of a part of a cylindrical surface. A light emitted from a light source is passed via the optical device and directed to an optical information storage medium, and a signal light is split from a return light from the optical information storage medium by the optical device.

Optical information storage apparatus and optical device including a beam splitting surface with a convex surface side and a concave surface side

An optical part has an exit surface from which beams of light applied through an incident surface are emitted, and a transmission film permitting the beams of light emitted from the exit surface to be transmitted at higher transmittance with higher light intensity. The exit surface is covered by the transmission film.

Optical head, optical part, and optical memory apparatus having controlled optical intensity

It is an object of the present invention to provide an optical information storage device capable of performing stable information accessing at a high recording density, and an optical head, and the optical information storage device and the optical head of the present invention comprise: a light shielding body held in a position close to/in contact with a surface of a recording medium, and provided with a slit adapted to intersect a track of the recording medium by an angle &agr; of 45&deg; or lower; condensing means for condensing a light emitted from a light source on the slit of the light shielding body; and moving means for moving the light S condensed on the slit by the condensing means along the slit.

Optical information storage device and optical head

The present invention relates to a recording head for recording information based on an optical magnetic recording system, and has an object of carrying out a high-density recording by reducing the beam diameter of an optical beam irradiated to a recording medium. When an optical beam having a larger diameter than that of the recording head is irradiated, this optical beam is condensed in a light guiding layer. The optical beam is further condensed with a sharp-headed chip. The condensed optical beam is emitted from an emission aperture smaller than the wavelength of the light at the front end of the chip, and irradiated to the recording medium.

Recording head for optical recording system

An optical apparatus can eliminate offset resulting from assembling errors and also can correct offset even in the photodetector of any optical system. An optical disk apparatus for reading information from tracks traces the track with the condensed spot of light beam depending on the tracking error signal obtained from the optical system for tracking error detection. The tracking error detecting optical system includes an optical apparatus having a photodetector for outputting, as the tracking error signal, a differential value of outputs of a plurality of light receiving sections for receiving the light beam condensed by the condenser lens. Also, an optical element is provided for relatively increasing and/or decreasing the amount of receiving light of a light receiving section depending on displacement of the optical axis of the light beam, in order to balance the light received by the light receiving sections and compensate for affect.

Growing community of inventors

Kawasaki, Japan

Wataru Odajima