Hitachi, Ltd.

Hideo Ohnuki

Toshimitsu Kaku

Akihiro Asada

Hidehiko Kando

Takashi Hoshino

Masaaki Kurebayashi

Yasuhito Tanaka

Hitoshi Watanabe

Norio Hosaka

Jun Yamada

Makoto Katagishi

Isao Akitake

A laser drive integrated circuit and an optical disk apparatus using the laser drive integrated circuit for forming high-density marks. The optical disk apparatus includes a drive waveform information storage unit for storing at least one information of a drive waveform for driving a laser diode in response to a binary recording signal to be recorded in a recording medium, and a drive waveform decoder for decoding the drive waveform based on the information stored in the drive waveform information storage unit. A recording strategy can be changed in accordance with variations and fluctuations of recording media or characteristics of the recording media, while at the same time reducing a number of signal lines in flexible wiring and alleviating effects of signal distortion in the signal lines.

Laser drive integrated circuit and optical disk apparatus using the same

A laser drive circuit includes a first current supply unit which supplies a first drive current to a first laser diode based on a drive waveform signal generated by a drive waveform generating unit, a second current supply unit which supplies a second drive current to a second laser diode based on the drive waveform signal generated by the drive waveform generating unit, and a switching unit which selectively supplies the drive waveform signal generated by the drive waveform generating unit to one of the first current supply unit and the second current supply unit. The drive waveform generating unit may be part of the laser drive circuit, or may be separate from the laser drive circuit, and may include a drive waveform information storage unit which stores a recording strategy according to a type of disk.

A laser drive integrated circuit and an optical disk apparatus using the laser drive integrated circuit for forming high-density marks. The optical disk apparatus has a drive waveform information storage unit for storing at least one information of the drive waveform for driving a laser diode in response to a binary recording signal recorded in a recording medium and a drive waveform decoder for decoding the drive waveform based on the information stored in the drive waveform information storage unit. The recording strategy can be changed in accordance with the variations and fluctuations of recording media or the characteristics of the recording media, while at the same time reducing the number of signal lines of flexible wiring and alleviating the effect of the signal distortion.

A high-frequency apparatus usable as a branching filter, branching filter module and/or a radio communication apparatus. The high-frequency apparatus includes a conductor substrate, a first dielectric layer provided on the conductor substrate, a strip conductor provided on the first dielectric layer, and a second dielectric layer provided on the strip conductor and having through holes provided therein. At least one elastic surface-wave element is provided over the second dielectric layer in a position above the strip conductor and is connected to the strip conductor by the through holes.

Branching filter, branching filter module and radio commnication

A plurality of interdigital transducers (IDTs) of a surface acoustic wave bandpass filter, each of which has a plurality of electrode fingers arranged in a direction perpendicular to a propagating direction of surface acoustic wave, are connected alternatively to an input terminal and an output terminal of said filter. The IDTs are different in number of electrode fingers and in average value of inter-finger distance from each other and distance between adjacent IDTs are different. At least one of the outermost IDTs has a minimum number of electrode fingers and a maximum average value of inter-finger distance, compared with those of other IDTs.

Saw filter and mobile telephone using same

A device for displacing and supporting a driven member pickup head in all the coordinate axis directions of three coordinate axes perpendicular to one another. The device includes at least one support member formed of viscoelastic material for supporting the driven member on a frame. The support member is tensioned and connected between the driven member and the frame and has one end affixed to the driven member disposed in a plane perpendicular to an arbitrarily selected one coordinate axis of the three coordinate axis directions and the other end affixed to the frame disposed in a plane perpendicular to the one coordinate axis. The pickup actuator also includes a device for generating lines of magnetic force in two directions perpendicular to each other, a first coil and a second coil secured to the driven member and having a first path of current and a second path of current respectively disposed in one direction of the magnetic lines of force and perpendicular to each other in a plane perpendicular to the one direction of the magnetic lines of force, a third coil secured to the driven member and having a third path of current disposed in the other direction of the lines of magnetic force and parallel to one of the first path of current and the second path of current in a plane perpendicular to the other direction of the lines of magnetic force, whereby the pickup holder can be independently driven for movement in three axis directions perpendicular to one another.

Growing community of inventors

Yokohama, Japan

Hideo Ohnuki