Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Denki K.k.

Kenjiro Kime

Keiji Nakamura

Masahisa Shinoda

Toshiya Matozaki

Nobuo Takeshita

Yoshinobu Ishida

Takeshi Ito

Toru Yoshihara

Kazuo Mori

Tetsuro Nagami

Kimihide Nakatsu

Kiyoshi Yanagiguchi

Hajime Nakajima

Kazuo Okada

Akira Hashimoto

Isao Watanabe

Teruo Fujita

Hideaki Kobachi

Kazuhiko Nakane

Masaharu Ogawa

Eiji Yokoyama

Norihiro Watanabe

Shigekazu Sakabe

Kouichi Komawaki

Morihiro Karaki

Hiroo Shimegi

Mitsuru Irie

Mitsushige Kondou

Naoyuki Egusa

Takeshi Utakouji

A turntable is a table mounted to a shaft (,) of a spindle motor and the turntable supports a laminated disc thereon and drives the disc in rotation. The laminated disc includes a lower disc and an upper disc stacked on the lower disc, and is supported on a disc-supporting surface. When the disc is loaded on the turntable, a fitting member fits into the center hole of the laminated disc for centering the laminated disc with respect to the shaft. The fitting member fits the center hole of the lower disc when the laminated disc is supported on said disc-supporting surface. The turntable may include a tapered member which guides the laminated disc to the disc-supporting surface. The laminated disc includes lower and upper discs each having an edge which defines the center hole. The corners of the edges are cut away along a circumference of the center hole. The upper and lower discs are placed together so that the cut-away corner directly face each other.

Laminated optical disc and turntable for the laminated optical disc

A turntable is a table mounted to a shaft (4) of a spindle motor and the turntable supports a laminated disc thereon and drives the disc in rotation. The laminated disc includes a lower disc and an upper disc stacked on the lower disc, and is supported on a disc-supporting surface. When the disc is loaded on the turntable, a fitting member fits into the center hole of the laminated disc for centering the laminated disc with respect to the shaft. The fitting member fits the center hole of the lower disc when the laminated disc is supported on said disc-supporting surface. The turntable may include a tapered member which guides the laminated disc to the disc-supporting surface. The laminated disc includes lower and upper discs each having an edge which defines the center hole. The corners of the edges are cut away along a circumference of the center hole. The upper and lower discs are placed together so that the cut-away corner directly face each other.

The reference character 5 denotes a supporting shaft holding base, which holds the lower end of a supporting shaft 103 coated with fluororesin with a small frictional coefficient. The reference characters 107a and 107b are tracking magnets bipolar-magnetized in the right and left direction, which are fixed to a fixing base 1 by bonding. The character 108 denotes a mirror for reflecting a light beam 2 incident from the front in the vertical upward direction. The character 6 denotes a lens holder formed of a plastic material, or the like, with light weight and high stiffness, which holds objective lenses 3 and 4 corresponding to a plurality of optical information recording media with different substrate thicknesses and different recording densities at positions eccentrically displaced by almost equal distances from the supporting shaft 103.

Optical information processing device having switchable optics for use

A turntable is a table mounted to a shaft (4) of a spindle motor and the turntable supports a laminated disc thereon and drives the disc in rotation. The laminated disc includes a lower disc and an upper disc stacked on the lower disc, and is supported on a disc-supporting surface. When the disc is loaded on the turntable, a fitting member fits into the center hole of the laminated disc for centering the laminated disc with respect to the shaft. The fitting member fits the center hole of the lower disc when the laminated disc is supported on the disc-supporting surface. The turntable may include a tapered member which guides the laminated disc to the disc-supporting surface. The laminated disc includes lower and upper discs each having an edge which defines the center hole. The corners of the edges are cut away along a circumference of the center hole. The upper and lower discs are placed together so that the cut-away corner directly face each other.

An optical device inclination angle adjuster for adjusting an optical axis of an optical device. The optical device has an optical axis and a peripheral portion, and is held by a holder. The adjuster includes an annular plate inserted between the optical device and the holder. The annular plate is in alignment with the peripheral portion of the optical device, and has an opening with an axis in alignment with the optical axis of the optical device to permit passage of light through the opening of the annular plate and through the optical device. A first pair of projections are formed between the annular plate and the optical device. The first pair of projections are disposed diametrically opposite to each other with respect to the optical axis and project in a direction parallel to the optical axis. A second pair of projections are formed between the annular plate and the holder. The second pair of projections are disposed diametrically opposite to each other with respect to the optical axis and project in a direction parallel to the optical axis. The first pair of projections and the second pair of projections are disposed at different rotary angles about the optical axis; whereby the inclination angle is adjusted by rotating the optical device about the first pair of projections or about the second pair of projections.

Optical device inclination angle adjuster

An optical recording and reproducing apparatus uses a laser to form one or more spots on an information recording medium preformatted with wobbling guide grooves, and detects tracking error. If the differential push-pull method of detecting tracking error is used, a center spot is flanked by satellite spots distant by an odd multiple of half the repeating period of tile wobble. If the three-beam method is used, the distance is an odd multiple of one-fourth the repeating period of the wobble. If the push-pull method is used, a split photodetector generates a pair of electrical signals. The sum and difference of these signals are filtered, then synchronously detected, and the result is combined with the difference signal to generate a corrected tracking error signal.

Optical recording and reproducing apparatus for tracking wobbling guide

An optical recording and reproducing apparatus uses a laser to form one or more spots on an information recording medium preformatted with wobbling guide grooves, and detects tracking error. If the differential push-pull method of detecting tracking error is used, a center spot is flanked by satellite spots distant by an odd multiple of half time repeating period of tile wobble. If tile three-beam method is used, the distance is an odd multiple of one-fourth the repeating period of the wobble. If the push-pull method is used, a split photodetector generates a pair of electrical signals. The sum and difference of these signals are filtered, then synchronously detected, and the result is combined with the difference signal to generate a corrected tracking error signal.

An optical head for recording, reproducing or erasing data by emitting a light beam irradiated from a light source onto a recording medium. To reduce the height of the optical head, an optical axis shifting device is disposed between a light beam emitting device and a condensing device for condensing the light beam onto the recording medium. This optical axis shifting device shifts the first optical axis of the light beam from the light beam emitting device to a second optical axis positioned in parallel and spaced apart from each other. As the optical axis shifting device, there is preferable employed a prism having two reflecting faces lying in parallel, and the optical axis, after shifting is to be positioned downwardly of the position of the optical axis before shifting, thereby reducing the height of the optical head.

Optical head

Magneto-optical disk recording and reproducing devices and actuators and distance detectors for use therewith are disclosed. The mageneto-optical disk device comprises, in addition to the usual elements, a bimorph type actuator or an electromagnetic actuator for driving the magnetic head of the magneto-optical disk device. The bimorph actuator has a metallic shim whose width varies with respect to the longitudinal distance inversely porportional to the normal function of the first or the second free natural vibration mode. Alternatively, the bimorph type actuator have a recess formed on a bimorph element to expose a piezoelectric crystal which outputs a voltage corresponding to the acceleration of the vibration of the actuator; the driver circuit of the actuator reduces the driving voltage when the frequency of the voltage generated at the recess comes into the neighborhood of a higher resonance frequency of the actuator. The optical distance detector comprises a light-emitting diode and a pair of photodiodes which detects the amount of light incident thereon after being reflected at a surface of an object the distance to which is measured. The geometric parameters of the photodiodes are selected in such a manner that the output of a first photodiode decreases as the measured distance increases while the output of a second photodiode increases as the measured distance increases. Thus, the normalized differential output of the two photodiodes, from which the measured distance is determined, varies substantially linearly with respect to the measured distance. In preferred forms, the photodetectors have stepped concentric configurations so that small distances can be measured accurately and efficiently.

Magneto-optical recording/reproducing system having an electromagnetic

An optical recording and reproducing apparatus uses a laser to form one or more spots on an information recording medium preformatted with wobbling guide grooves, and detects tracking error. If the differential push-pull method of detecting tracking error is used, a center spot is flanked by satellite spots distant by an odd multiple of half the repeating period of the wobble. If the three-beam method is used, the distance is an odd multiple of one-fourth the repeating period of the wobble. If the push-pull method is used, a split photodetector generates a pair of electrical signals. The sum and difference of these signals are filtered, then synchronously detected, and the result is combined with the difference signal to generate a corrected tracking error signal.

Magneto-optical disk recording and reproducing devices and actuators and distance detectors for use therewith are disclosed. The magneto-optical disk device includes a bimorph type actuator or an electromagnetic actuator for driving the magnetic head of the magneto-optical disk device. The bimorph actuator has a metallic shim having a width that varies with respect to the longitudinal distance in inverse proportion to the normal function of the first or the second free natural vibration mode. Alternatively, the bimorph type actuator has a recess formed on a bimorph element to expose a piezoelectric portion which outputs a voltage corresponding to the acceleration of the vibration of the actuator. The driver circuit of the actuator reduces the driving voltage when the frequency of the voltage generated at the recess comes into the neighborhood of a higher resonance frequency of the actuator. The optical distance detector comprises a light-emitting diode and a pair of photodiodes which detects the amount of light incident thereon after the light is reflected from a surface of an object the distance to which is measured. The geometric parameters of the photodiodes are selected such that the output of a first photodiode decreases as the measured distance increases while the output of a second photodiode increases as the measured distance increases. Thus, the normalized differential output of the two photodiodes, from which the measured distance is determined, varies substantially linearly with respect to the measured distance. In preferred forms, the photodetectors have stepped concentric configurations so that small distances can be measured accurately and efficiently.

Magneto-optical recording and reproducing disk device having a bimorph

An optical head which optically records and regenerates data by condensing light beams from a light source on the disk surface, wherein a plurality of piezoelectric elements are arranged to correct the tilt of a condensing lens or the tilt of optical system supporting means for making the optical axis of the condensing lens for condensing light beams on the disk surface or the light beams orthogonal to the disk surface. An optical disk drive provided with an optical head, wherein a plurality of piezoelectric elements are arranged to correct the tilt of the disk for making the optical axis of a condensing lens which condenses light beams on the disk surface orthogonal to the disk surface.

Apparatus for maintaining a disk and optical head in orthogonal relation

Objective lens driving device

An objective lens driving device with a multipole magnet which includes a cylindrical yoke with an E-shaped cross section for defining an annular gap between the central yoke section and the outer cyclindrical yoke section; four rectangular tracking coils attached to the side of a focusing coil such that a pair of vertical coil sides of each tracking coil are parallel to a supporting shaft; and a pair of circular multipole magnets disposed within the gap between the central and outer cylindrical yoke sections and each having at least three magnet sections, with opposite end magnet sections having a polarity opposite to that of the central magnet section so that the vertical coil sides interlink with magnetic fluxes having opposite directions to each other, whereby tracking forces act upon the vertical coil sides in the same direction.

Objective lens driving device with multipole magnet

An optical signal reading device comprising a laser light source (101), an objective (107) slidable in the direction of the optical axis which is at right angles to the disc surface of a disc-like record carrier, a light detector (110) for receiving the reflected light coming from the disc surface via the objective, and a beam splitter (104) comprised of a single optical part disposed between the light source (101), light detector (110), and objective (107). The splitter has a pair of reflecting surfaces disposed approximately parallel to each other to ensure that the incident light from the light source (101) and the reflected light guided to the light detector (110) are parallel and opposite to each other.

Growing community of inventors

Nagaokakyo, Japan

Kenjiro Kime