Mitsubishi Denki Kabushiki Kaisha

Mitsuru Irie

Morihiro Karaki

Nobuo Takeshita

Kazuhiko Nakane

Teruo Fujita

Hideaki Kobachi

Toru Yoshihara

Shigenori Yagi

Masahisa Shinoda

Akihiro Shima

Kenjiro Kime

Akira Ishimori

Naoyuki Egusa

Manabu Koike

Yasuyuki Satou

Takeshi Utakouji

A light source ( ) is composed of a single element having a light emitting point ( S) emitting a light ( S) and a light emitting point ( L) emitting a light ( L) at a longer wavelength than the light ( S), the light emitting point ( S) and the light emitting point ( L) being formed monolithically. In the direction parallel to the optical axis of a collimator lens ( ), the light emitting point ( S) is placed closer, than the light emitting point ( L), to the collimator lens ( ) and is placed on the side of the inclined plane ( ) of the beam shaping prism ( ). The incidence angles of the light ( S) and the light ( L) to the inclined plane ( ) are set so that the incidence angle of the light ( S) is larger than that of the light ( L) and so that the lights ( S) and ( L) exit from the inclined plane ( ) at equal exit angles. The collimator lens ( ), the beam shaping prism ( ), etc. have refractive indexes which become larger as the wavelength of incident light becomes shorter. It is then possible to simplify the structure and reduce the unstableness of operation caused by a difference in light wavelength.

Optical head device

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

A focus error detecting device includes a reflected beam obscurer and a two-division photodetector. The observer obscures a part of the reflected beam. The two-division photodetector includes first and second light receiving sections separated from each other by a division band region which receive the reflected light beam not obscured by the obscurer. A focus error signal is produced based on the output of each light receiving section. Each light receiving section has an array of tapered projections along its edge in the division band region. Alteratively, the light receiving sections have a main part with an edge coincident with an edge of the division band region, and groups of light receiving stripes extending in a direction parallel with the edges of the main part.

Focus error detecting device

The second harmonic wave of a solid laser light which is emitted from a second harmonic wave light source is divided into a plurality of laser beams by a diffraction grating. The divided laser beams are converged on a record carrier into a plurality of light spots by an optical head. Magnetic field generating coils for applying magnetic fields to the respective light spots in accordance with the recording signals from a signal line are disposed under the record carrier. Part of the solid laser light is reflected and input to a beam splitter. Since part of the light input to the beam splitter is taken out, a stabilizer controls the output of the solid laser light from the second harmonic wave light source, parallel recording/reproduction using the plurality of light spots which are arranged on the record carrier is enabled and the formation of the plurality of light spots is effectively controlled. Thus, a magneto-optical recording and reproducing apparatus which is capable of high-density recording and high-speed data transfer, which supplies a stable and accurate optical output, and which facilitates the control of the optical output is provided.

Magneto-optical recording and reproducing apparatus

A lens actuating system for an optical disk drive has an objective lens movably mounted in a movable frame with orthogonal X-, Y-, and Z-axes. A seeking servo moves the frame in the X-direction. A tracking servo moves the objective lens in the X-direction. A focusing servo moves the objective lens in the Z-direction. An optoelectronic sensor detects the relative position of the objective lens and frame in the X-direction, so that the tracking servo can maintain a fixed relative position during track-seeking, or in the Z-direction, to establish a neutral point on the Z-axis for the focusing servo. Force applied by the focusing servo or tracking servo to move the objective lens in one direction can be opposed by an equal and opposite force applied to a driven mass, so that a net zero force is transmitted to the frame.

Lens actuating system for an optical disk drive having a driven mass for

A focus error detecting device includes a reflected beam splitter and at least two two-division photodetectors. The reflected beam splitter includes a diffraction grating part and a non-diffraction grating part separated by a line dividing a reflected beam. The dividing line projects to a line orthogonal to a guide groove on the information recording medium. The diffraction grating part produces a first split beam, and non-diffraction grating part produces a second split beam. Each two-division photodetector receives one of the first and second split beams incident and their light receiving sections, and produces a signal for effecting focus control.

Growing community of inventors

Nagaokakyo, Japan

Mitsuru Irie