Sony Corporation

Seishi Gijutsu Kenkyu Kumiai

Masami Yuasa

Etsuro Saito

Tsutomu Akiyama

Tsutomu Maruyama

Shinichiro Takahashi

Masahiro Yakabe

Kazumi Abe

Yoshiki Takemoto

Masaji Shibamoto

After making such adjustment that an a main push-pull signal MPP offset can be made zero when a main beam is positioned at the center of a main photoreceptor, using electric signals E and F photoelectrically converted by one of two two-divided side beam photoreceptors and electric signals H and G photo-electrically converted by the other thereof, a side push-pull signal SPP including a constant &#x3b1; is determined for allowing respective (F&#x2212;&#x3b1;E) and (&#x3b1;H&#x2212;G) offsets to be made zero and is calculated according to the formula, SPP&#x2212;(F&#x2212;&#x3b1;E)+(&#x3b1;H&#x2212;G). From this SPP signal and the main push-pull signal MPP, a differential push-pull signal DPP is then calculated, thereby allowing stable tracking control to be carried out, even during recording.

Optical pickup apparatus, optical disc apparatus, and tracking control method thereof

A recording and reproducing apparatus includes a semiconductor laser device for irradiating a light beam, a driving circuit for driving the semiconductor laser device, and an oscillation device for generating a predetermined high-frequency signal. The high-frequency signal generated by this oscillation device is superposed onto a driving signal of the driving circuit in order to drive the semiconductor laser device.

Output control apparatus of semiconductor laser device

A plurality of stages of parallel twisted plates extend in a slurry passage adjacent to a slice outlet of a head box in the direction of papermaking slurry flow therethrough and are spaced apart from each other by a predetermined distance. The twisted plates directly cause the slurry flowing through the head box to swirl. Adjacent vortex flows of the slurry interfere with each other, resulting in the violent agitation of the slurry.

Headbox for paper machine with parallel twisted plates

A brushless motor comprises a magnet having a plurality of pole faces, a plurality of conductors mounted adjacent to the pole faces, and a plurality of phase coils connected together at a neutral point. The magnet is included in the motor rotor and the phase coils are included in the motor stator. A high-frequency signal source supplies a high-frequency signal to the neutral point, whereby changes in eddy current loss and thus the position of the rotor with respect to the stator are detected.

Brushless motor

A magnetic recording apparatus includes a rotary disc rotatable about an axis and having an outwardly extending radial flange with three apertures therein; three pins mounted in the apertures on the rotary disc and positioned about a circle concentric with the axis for accurately supporting an information record disc thereon, each of the three pins projecting from the rotary disc to substantially the same height; and a magnet positioned on the flange of the rotary disc and having a height lower than the three pins for magnetically attracting the information record disc to secure the latter on the three pins.

Growing community of inventors

Chiba, Japan

Masami Yuasa