Kabushiki Kaisha Sankyo Seiki Seisakusho

Sankyo Seiki Mfg. Co., Ltd

Nidec Sankyo Corporation

Yoshio Hayashi

Tadashi Takeda

Yuichi Takei

Hideo Takezoe

Ken Ishikawa

Hisahiro Ishihara

Taminori Masuzawa

Kazuo Higashiura

Takaaki Suzuki

Ikuo Kasuga

Kazuyoshi Yasukawa

Satoru Nakao

Atsuo Fukuda

Atsuhiro Hanaoka

Noriyuki Satoh

An optical head device including a lens holder which holds an objective lens, six wires for supporting the lens holder and a holder support member which movably supports the lens holder by the six wires in a tracking, focusing and tilt direction. The six wires comprise two pairs, each of the pairs comprising a composite wire composed of two wires and a single wire composed of one wire which are respectively disposed on an upper side and a lower side of the lens holder in the focusing direction. The spring constant of the composite wire is set to be approximately equal to a spring constant of the single wire. Alternatively, the six wires may be disposed on the same circumference with respect to a drive center in the tilt direction or the spring constant of one wire of the pair may be set to be smaller than spring constants of the other two wires of the pair.

Optical head device having an objective lens holder supported by composite wires and single wires

An optical pickup device includes a semiconductor laser for emitting forward and backward laser light from front and back emergent end faces thereof, focusing device for focusing the forward laser light emergent from the front emergent end face of said semiconductor laser onto an optical recording medium, a light-receiving element for signal reproduction for detecting return light from the optical recording medium, and a light-guiding system for guiding the return light to said light-receiving element for signal reproduction, said optical pickup device being provided with a light source unit having an arrangement in which said semiconductor laser and said light-receiving element for signal reproduction being incorporated in a common package and shielding device, disposed inside said package of said light source unit, for preventing the light emitted from said semiconductor laser from being incident upon said light-receiving element for signal reproduction.

Optical pickup device

A phase difference plate ( ) converts states of polarization of emergent light form a laser light source ( ) and return light form an optical recording medium ( ). A diffractive element ( ) separates the return light from an optical axis leading from the laser light source ( ) to the optical recording medium ( ), and guides the return light to a photodetector ( ) on the basis of a difference between the states of polarization of the emergent light and the return light. The polarization direction of emergent light from the laser light source ( ) is arranged so as to be oriented in the radial direction of the optical recording medium ( ) (in the direction of birefringence of the optical recording medium). The azimuth and the amount of phase of the phase difference plate ( ) are set so that a peak of a signal in tensity detected by the photodetector ( ) appears while an amount of birefringence of the optical recording medium changes from 0 to a quarter wavelength of the laser light when the amount of birefringence of the optical recording medium ( ) is changed.

Optical pickup device having a shielding protection

A returning light beam from an optical disc is divided by a separating diffractor in the directions perpendicular to a track direction of the optical recording medium, and according to respective illuminances of the divided light beams, a deviation amount of an objective lens to an optical axis is detected. By feedback-controlling an objective lens driver by using the information of the detected deviation amount, the objective lens can be made to become stationary at the desired position in a short time. Accordingly, a time period required for the oscillation attenuation of the objective lens can be shortened, thereby, a time period for the reproduction can be shortened.

Light-pick-up device and light source unit incorporated in the same

A semiconductor laser apparatus comprises a semiconductor substrate, a semiconductor laser which is fixed on the semiconductor substrate and a prism having a slanted plane. The prism is placed such that its slanted plane faces a side across from the semiconductor laser. The apparatus also includes an optical detector for monitoring which is formed on the surface of the semiconductor substrate. The surface is covered by the prism. The following are formed on the slanted plane of the prism: a reflection region on which the surface is processed for reflecting a part of an emitted light beam from the semiconductor laser and a transmissive refraction region on which the surface is processed such that the remaining part of the emitted light beam is transmitted and refracted to be guided to a light receiving plane of the optical detector for monitoring.

Semiconductor laser apparatus and optical pickup apparatus

An optical head assembly comprises a laser light source, an objective lens for converging a laser light emitted from the laser light source on an optical recording medium, an optical detector for detecting a returning light from the optical recording medium, a diffraction unit mounted in an optical path between the laser light source and objective lens for positioning multiple diffraction grating means, a base of the optical head assembly for supporting the objective lens, the laser light source and the optical detector, and a diffraction grating unit retaining portion formed on the base for holding the diffraction grating unit.

Optical head assembly

An optical pickup head apparatus for reading information signals from a recording medium having a laser beam light source, an objective lens and a photodetector, the improvement comprises a holographic optical element constructed of a pair of diffraction gratings having different diffractive conditions wherein the element is split into two by a split line near its optical axis as a border and a diffraction generation prevention device for preventing the generation of unwanted diffracted beams from a recording medium. The optical pickup head apparatus irradiates a laser beam emitted from the light source onto a recording medium via the holographic optical element and the objective lens. Beams reflected from the recording medium are guided to the photodetector via the objective lens and the holographic optical element.

Optical pickup head apparatus

A polarizing beam-splitter comprises an optically isotropics crystalline substrate and a birefringent material layer made of an oriented polydiacetylene film formed on the optically isotropic crystalline substrate. A periodic grating photo-mask is formed in the birefringent material layer by an area that is changed into a different color phase when an ultra violet light is irradiated in a predetermined pattern on the birefringent material layer and by an area in which the color remains unchanged. The periodic grating photo-mask has a diffraction efficiency for the orientation of the oriented polydiacetylene film in the area that is changed into a different color phase which is lower than that in the area in which the color is unchanged.

Polarizing beam splitter and method for manufacturing same

An optical pickup device includes a light source irradiating a record medium with plural light spots of light emitted therefrom, a plurality of light detecting elelments to which reflected light of the light spots are guided, respectively, to adequately synthesize and compare outputs of said light detecting elements, thereby reading information recorded in tracks of the record medium, and detecting an tracking error and a focusing error, and a hologram element which splits light emitted from the light source into plural beams is disposed in an optical path between the light source and the record medium, said hologram element is split by a split line, said split line elongating in a direction perpendicular to a track of the medium on an optical axis, and a hologram pattern having a diffraction function which is substantially directed in the track direction is disposed on at least one side of said split line, thereby differentiating diffraction conditions on both sides of said split line from each other.

Optical pickup device with split hologram element that diffracts light

A polarizing beam splitter includes: an optically isotropic substrate; a layer of birefringent material formed on top of said optically isotropic substrate; and a periodic pattern of ridges and grooves formed on a surface of said optically isotropic substrate to make a grating; and a refractive index equal to either the refractive index of the birefringent material for ordinary light or the index for extraordinary light, said grooves being filled with the material.

Polarizing beam splitter and optical head assembly

A tracking error signal and a focus error signal can be obtained with those components of the light (plus and minus first-order light) which have been diffracted by a hologram device whereas the undiffracted zero-order light component is for the sole purpose of producing RF signals. As a result, RF signals can be detected without using a segmented photodetector while insuring that output signals of a constant intensity are produced even if there are changes in the spot diameter and position. In addition, any aberrations that are caused by an half-mirror are corrected by optics that is provided in the optical path connecting the half-mirror and the light-receiving elements of a photodetector and this insures that even if an objective lens moves, detection spots on the individual light-receiving elements will move on the latter without causing any offset errors.

Optical pickup system

In an optical pickup system, the light emitted from a source to illuminate an optical recording medium is reflected and directed via a beam splitter to a photodetector so as to read information signals, and a hologram device for splitting the emerging light from the source into a plurality of beams is provided as an integral part of the entrance surface of the beam splitter.

Hologram integrated with a beam splitter to separate a plurality of

A process for controlling an industrial robot in which most data for controlling the robot can be supplied using a preset process without moving the robot and only data for regions in which very precise control is required need be prepared by actually moving the robot. A programming unit is provided separate from but connectable to a robot control unit. The programming unit is used to compile and transfer completed programs to the robot control unit for controlling the movements of the robot. To program the robot control unit, the programming unit and robot control unit are connected as an on-line system. Then, data describing a desired path of movement is inputted to the programming unit as a series of coordinates in Cartesian form. In regions where very precise control is required, the coordinates describing the desired path of movement are corrected using small corrective motions of the robot. The inputted data and the corrected coordinates are displayed.

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Nagano, Japan

Yoshio Hayashi