Abstract: The hole that penetrates the axial direction in the hub, the force of the axial direction by fluid force that operates on the spindle motor is reduced during the rotation. Fluctuation of fluid power is reduced by this hole. The rotary precision of the axial direction improves. Against the oil leakage from the bearing equipment, magnetic fluid is used as a lubrication fluid of the bearing. Magnetic fluid is magnetized with the permanent magnet arranged in the bearing equipment, and oil leakage is prevented. Against scattering of the oil particle, the groove for dynamic pressure generation is in the opening of bearing equipment. The oil particle is kept inside the bearing equipment.

Abstract: A disk drive unit includes a rotary member, which has a spindle, and has an information-recording disk fixedly mounted thereon, and a bearing unit rotatably supporting the spindle. The bearing unit includes a radial bearing device, provided in opposed relation to an outer peripheral surface of the spindle, and a thrust bearing device provided in opposed relation to a distal end surface of the spindle. The radial bearing device has a concentric arc-shaped bearing surface, which is concentric with the circular outer periphery of the spindle, and a non-concentric arc-shaped bearing surface which is non-concentric with the circular outer periphery of the spindle. The disk drive unit further includes a motor for imparting a rotational force to the spindle, and a lubricating fluid filled in the bearing unit.

Abstract: A disk drive unit includes a rotary member, which has a spindle, and has an information-recording disk fixedly mounted thereon, and a bearing unit rotatably supporting the spindle. The bearing unit includes a radial bearing device, provided in opposed relation to an outer peripheral surface of the spindle, and a thrust bearing device provided in opposed relation to a distal end surface of the spindle. The radial bearing device has a concentric arc-shaped bearing surface, which is concentric with the circular outer periphery of the spindle, and a non-concentric arc-shaped bearing surface which is non-concentric with the circular outer periphery of the spindle. The disk drive unit further includes a motor for imparting a rotational force to the spindle, and a lubricating fluid filled in the bearing unit.

Abstract: In a magnetic disk apparatus, the spindle motor is provided with a hole that penetrates the hub in the axial direction thereof. The hole permits fluid pressure on the outside and inside of the hub to become balanced, reducing the axial fluid force caused by the rotation of the spindle motor. The apparatus further includes a bearing provided with a groove for dynamic pressure generation and a magnetic lubrication fluid which, in combination with a permanent magnet, prevents oil leakage and scattering.

Abstract: A disk drive unit includes a rotary member, which has a spindle, and has an information-recording disk fixedly mounted thereon, and a bearing unit rotatably supporting the spindle. The bearing unit includes a radial bearing device, provided in opposed relation to an outer peripheral surface of the spindle, and a thrust bearing device provided in opposed relation to a distal end surface of the spindle. The radial bearing device has a concentric arc-shaped bearing surface, which is concentric with the circular outer periphery of the spindle, and a non-concentric arc-shaped bearing surface which is non-concentric with the circular outer periphery of the spindle. The disk drive unit further includes a motor for imparting a rotational force to the spindle, and a lubricating fluid filled in the bearing unit.

Abstract: A pad for controlling the state of contact or flying of a slider with or to an information-recording medium and a probe for exciting near-field light having a small spot size are mounted on the slider and the pad is near to the probe. Semiconductor laser light focused by an objective lens is converted into near-field light having a small spot size near the top of the probe for exciting near-field light. The slider travels at a height of several tens nm to a recording medium substrate and information is recorded or read out on or from the information-recording medium formed on the recording medium substrate.

Abstract: A disk drive unit includes a rotary member, which has a spindle, and has an information-recording disk fixedly mounted thereon, and a bearing unit rotatably supporting the spindle. The bearing unit includes a radial bearing device, provided in opposed relation to an outer peripheral surface of the spindle, and a thrust bearing device provided in opposed relation to a distal end surface of the spindle. The radial bearing device has a concentric arc-shaped bearing surface, which is concentric with the circular outer periphery of the spindle, and a non-concentric arc-shaped bearing surface which is non-concentric with the circular outer periphery of the spindle. The disk drive unit further includes a motor for imparting a rotational force to the spindle, and a lubricating fluid filled in the bearing unit.

Abstract: An optical switch for switching an optical path of an input optical signal comprises a substrate composed of a silica glass substrate, a separation layer formed on the silica glass substrate, a plurality of cantilever beams and formed in parallel to one another on the separation layer and connected at their tip ends to a connection member, at least one silica glass optical waveguide core formed on the cantilever beams, a plurality of optical waveguide fixed in opposition to the silica glass optical waveguide core, a cover for covering the cantilever beams, and a switch drive unit for bending the cantilever beams. The switch drive unit comprises electromagnetic actuators, which comprise soft magnetic bodies formed on the connection member for the cantilever beams and on the substrate, soft magnetic yokes formed of a soft magnetic body, permanent magnets, and wire coils.

Abstract: A disk drive unit includes a rotary member, which has a spindle, and has an information-recording disk fixedly mounted thereon, and a bearing unit rotatably supporting the spindle. The bearing unit includes a radial bearing device, provided in opposed relation to an outer peripheral surface of the spindle, and a thrust bearing device provided in opposed relation to a distal end surface of the spindle. The radial bearing device has a concentric arc-shaped bearing surface, which is concentric with the circular outer periphery of the spindle, and a non-concentric arc-shaped bearing surface which is non-concentric with the circular outer periphery of the spindle. The disk drive unit further includes a motor for imparting a rotational force to the spindle, and a lubricating fluid filled in the bearing unit.

Abstract: An optical switch for switching an optical path of an input optical signal comprises a substrate composed of a silica glass substrate, a separation layer formed on the silica glass substrate, a plurality of cantilever beams and formed in parallel to one another on the separation layer and connected at their tip ends to a connection member, at least one silica glass optical waveguide core formed on the cantilever beams, a plurality of optical waveguide fixed in opposition to the silica glass optical waveguide core, a cover for covering the cantilever beams, and a switch drive unit for bending the cantilever beams. The switch drive unit comprises electromagnetic actuators, which comprise soft magnetic bodies formed on the connection member for the cantilever beams and on the substrate, soft magnetic yokes formed of a soft magnetic body, permanent magnets, and wire coils.

Abstract: An optical disk drive has an aberration detector and an aberration correction circuit. A semiconductor laser device made of semiconductor crystals constituting a semiconductor laser light source includes an active layer for performing light amplification through current injection and guiding light in waveguide, a reflection member for reflecting light into said active layer, and a top electrode and a bottom electrode used for current injection to the active layer, wherein the top electrode is divided into a main electrode and a plurality of subsidiary electrodes, and injection current to the subsidiary electrodes is controlled so as to correct an aberration generated at an optical focussing system and an optical disk.

Abstract: In an optical scanning type tunneling microscope, reference light is prepared in addition to light used to be projected to a sample, and this reference light and also light picked up from an optical probe are caused to interfere with each other. As a result, phase information of light about a region having a very smaller dimension than a wavelength of the light irradiated from alight source can be acquired.

Abstract: An optical pickup device includes a laser source for emitting linearly polarized light; an objective lens for focusing source light received from the laser source on an optical information storage medium; a photodetector for receiving signal light reflected from the medium for converting the signal light into an electric signal. The photodetector includes at least a photosensor, a planar optical waveguide formed on the photosensor for propagating the signal light therethrough, diffraction grating for diffracting the signal light propagating through the waveguide, and an incidence coupler provided on the waveguide for reflecting the source light emitted from the laser source and receiving signal light obtained through the objective lens from the medium.

Abstract: In a magneto-optical recording and reproducing apparatus, a magnetic field is applied to a laser source in the direction of extension of the optical axis of the laser source to radiate a circularly polarized light beam. A magneto-optical disk has a quantum well structure and records information on the disk with the circularly polarized light beam in a magneto-optical manner.

Abstract: An information processing apparatus such as an optical disc device which is provided with an integrated photo detector for transducing a reflected light beam from an optical information medium to an electric signal. The integrated photo detector used in the apparatus comprises a substrate; an optical guide formed on the substrate; and a plurality of integrated photo detecting sections each including a grating coupler for guiding the reflected light beam to the optical guide, and a photo detecting unit for detecting a guided light beam in the optical guide. The use of this integrated photo detector results in increasing error tolerance relative to incident angle and incident position to improve the incidence efficiency, thereby elevating the reliability of the apparatus.