Mitsubishi Denki Kabushiki Kaisha

Tetsu Yamamoto

Takashi Yumura

Takaharu Ueda

Manabu Ogura

Shigeki Mizuno

Kiyoshi Funai

Kiyosi Funai

Sadao Okada

Daisuke Ogata

Junji Kawada

Shuji Ogawa

Miki Kurosawa

Masayuki Sugahara

Hiroshi Imai

Yasushi Onooka

Nobuaki Maeda

Kouichi Yoshioka

Mayumi Nakazawa

A method and apparatus for detecting the machining status of a laser beam machining device, having a multi-mirror resonator for generating a machining beam, which utilizes the secondary light generated by the machining operation and returned from the workpiece surface into the resonator for control of the machining operation. The oscillator and accompanying components, such as beam dividing mirrors and splitters, are operative to separate the secondary light from the laser beam within the resonator and direct the two beams separately to detectors located outside of the resonator. Alternatively, the secondary light and laser beam may be directed to the outside together where they are separated by an integrating sphere for detection.

Laser machining apparatus and method

An assembly for supporting a magnetic head to float relative to a magnetic disk, comprises a load arm extending substantially tangentially of a magnetic disk and moved substantially radially of the magnetic disk, the load arm having a proximal end, and a distal end and including a spring portion at its proximal end, a gimbal secured to the distal end of the load arm and including a pivot, the load arm including a contact point at its distal end to contact with the pivot, and a magnetic head slider secured to the gimbal so as to pitch and roll about the pivot with movement of the magnetic disk. The magnetic head slider is adapted to support a magnetic head and is urged toward the magnetic disk under the influence of the spring portion of the load arm. The load arm has a shear center at the contact point.

Assembly for supporting a magnetic head to float relative to a magnetic

A positioning control apparatus comprises a feedback compensatory system and a feedforward compensatory system. The feedforward compensatory system comprises a detector for detecting a position of a controlled object whose position is to be controlled, and a compensator connected to the detector. The feedforward compensatory system comprises a first filter having a characteristics reverse to that of the feedback compensatory system, and a second filter having a characteristics reverse to that of the object. A desired drive signal generator supplies the feedforward compensatory system with a desired drive signal having a frequency spectrum having a minimum at the mechanical resonance frequency of the object.

Positioning control apparatus

A retract mechanism for a magnetic head which can read from and/or write to a disk, the mechanism includes a spring arm which supports the head and urges the head toward the disk. The spring arm includes a cam follower which rides along the surface of the cam, which has two parallel horizontal surfaces and two incline surfaces. The spring arm is moved by an actuator in a radial direction along the disk. When the spring arm is moved radially away from the center of the disk, the cam urges the spring arm upwardly, thereby lifting the head up and away from the disk. As the spring arm continues to move radially away from the center of the disk, the cam guides the spring arm such that the head rests safely on a landing platform.

Read/write head retract mechanism

A head positioning apparatus for a disc unit which moves a carriage having a movable portion by driving motors constituted by coils and magnets, wherein driving power distribution of the driving motors is variable, so that the acting points of the driving forces of the driving motors can be variably set at any position to position the acting points of driving forces of the driving motors on a centroidal axis of the movable portion.

Head positioning apparatus for disc unit

A carriage assembly has a carriage provided on both sides with voice coils, a magnet assembly surrounding the voice coils and adapted for causing the carriage to move in the radial direction of a disk, and guide rails for guiding the carriage in the radial direction of the disk. The carriage is provided on a lower portion thereof with first rollers for engagement with the guide rails and at its upper portion thereof with second rollers which co-operate with a biasing members in preventing the carriage from moving upward. Either the guide rails or the first rollers are provided with grooves which prevent the first rollers from moving in the tangential directions of the guide rails. Since the movement of the first rollers in the tangential directions of the guide rail is prevented, it is possible to locate the carriage with a high degree of precision with respect to the disk.

Carriage assembly

Provided is a reflector oscillating apparatus in which the positions of a reflector and a compensating plate are detected so as to perform positioning with a high degree of positional accuracy (closed-loop control). Further, since the reflector and the compensating plate are driven by a couple of forces, no reaction forces by drive forces are applied to a rotary shaft and a support section, and accordingly, it is possible to enhance the positioning accuracy and to realize a short transient time and a large amplitude. Further, the magnetic circuit is commonly used so that the dimensions of a motor, that is, the height thereof in particular, can be reduced, irrespective of a large drive force. Accordingly, the reflector oscillating apparatus can be greatly miniaturized. Further, by commonly using the magnetic circuit, the impedance of the coil can be reduced, thereby it is possible to drive the apparatus at a high speed with a low drive voltage.

Reflector oscillating apparatus

An in-line type magnetic head supporting apparatus of the present invention including a first fixed part secured to a magnetic head slider mounted with a magnetic head in a floatable manner, a second fixed part secured to a load beam which presses the magnetic head slider toward the magnetic disc, and a gimbal mechanism comprising a spring part connecting the first and second fixed parts and enabling the pitching and rolling movements of the magnetic head slider in the radial direction of the magnetic disc, and further includes a restricting mechanism for preventing the sideslip of a pivot formed on the first fixed part as a fulcrum for pitching and rolling movements. Furthermore, in order to increase the flexural rigidity of the spring part of the gimbal mechanism in the radial direction, its lateral length is enlarged and slits are formed in the spring part to reduce the torsional rigidity thereby to prevent the inteference of the pitching and rolling movements.

Magnetic head suspension assembly for reducing vibration effects

An object lens head assembly for use with an optical recording disc comprises an information conversion apparatus for receiving an electrical signal bearing information to be written to the disc and outputting beams of light bearing the information to be written to the disc, and for receiving a beam of light bearing information read from the disc and outputting an electrical signal bearing the information read from the disc; a plurality of object lenses disposed along a diametrical direction of the disc for directing light onto a plurality of portions of the disc, respectively; a plurality of reflective mirrors for reflecting the light beam output from the information conversion apparatus toward a selected one of the object lenses; a linear motor for moving the object lenses along the diametrical direction of the disc; and a light beam shifting mechanism for shifting the light beam so that the light beam impinges upon a selected one of the reflective mirrors.

Object lens head assembly

Document scanner driven by electromagnetic actuators

The positioning control apparatus includes a feedback compensatory compensatory system for performing high-accurate positioning and a feedforward compensatory system for carrying out high-speed output response. The feedforward compensatory system is provided with a dynamic characteristic of an object to be controlled and a dynamic characteristic reverse to that of a control system by a feedback compensation. Transfer characteristic from a position command to an output of the object is assumed to be 1. As a result, there can be easily obtained a desired output response as well as a desired control input.

An electromagnetic drive actuator including a magnetic circuit comprising at least one yoke having plate-shaped, L-shaped, E-shaped cross section or the like, at least one magnet mounted on the yoke and a magnetic flux extending from the magnet to the yoke, at least one coil arranged so as to cross the magnetic flux and produce a drive force in a direction crossing a plane including the magnetic path of the magnetic circuit when current is applied to the coil, and at least one magnetic shield member provided at the side portion of the coil to thereby prevent a counter drive force from being produced in a direction opposite to a desired direction of a drive force produced by the coil.

Electromagnetic drive actuator

A carriage assembly for use with an optical recording disc for optical recording and reproduction relative to the disc comprises a frame, an optical lens for projecting and receiving a light beam for the optical recording and reproduction, a carriage movably supported in the frame for supporting the optical lens relative to the disc, a vertical guide arrangement for permitting a movement of the optical lens relative to the carriage in a vertical direction relative the disc surface, a vertical drive arrangement for driving the optical lens in the vertical direction relative to the carriage, a radial guide arrangement for permitting said carriage to move in a radial direction of said optical disc, and a radial drive arrangement for driving the carriage in the radial direction of the disc. The vertical drive arrangement includes a permanent magnet and an electromagnetic coil electromagnetically coupled with the permanent magnet, one of the permanent magnet and the electromagnetic coil being mounted to the optical lens and the other of them being mounted to the frame, whereby the carriage assembly is reduced in both weight and physical dimensions.

A carriage assembly for a disc operating apparatus comprising a frame, a carriage movably supported in the frame relative to the disc, an optical lens or magnetic head mounted on the carriage for recording and reproducing information on the disc, and a radial guide arrangement permitting movement of the carriage in a radial direction relative to the disc. The assembly also comprises a radial drive arrangement including an electromagnetic coil mounted to the carriage and a permanent magnet mounted to the frame. The permanent magnet is electromagnetically coupled with the electromagnetic coil for driving the carriage in the radial direction of the disc. The electromagnetic coil includes two sections which sandwich the carriage and are shaped to come into contact with each other at both sides thereof, whereby the cross section of the electromagnetic coil is hexagonal in a plane parallel to a surface of the disc. As a result, the dimensions in the radial direction of the carriage assembly are decreased.

Carriage recording head sandwiched by electromagnetic coil sections

A head actuator for a disk drive is provided with a structural body integrally formed by a housing portion for rotatably supporting a moving part formed by a head for writing/reading data in/from a disk and a coil fixed therewith and a yoke portion for interlinking magnetic flux with the coil, which structural body is fixed to a base portion. By virtue of such structure, the resonance point of a vibration system of the head actuator can be increased in frequency thereby to stably and correctly locate the head on the disk. The structural body and base portion mount to each other on the surfaces which are substantially coplanar with the center of gravity and head arm direction of movement.

Growing community of inventors

Amagasaki, Japan

Tetsu Yamamoto