Sony Corporation

Yuhei Kobayashi

Kenji Yamamoto

Takashi Kobayashi

Takashi Fukushima

Noriaki Nishi

Fumiaki Henmi

Tomoyuki Ishida

Kazutaka Noborimoto

Tadashi Ohtsuki

Katsuhiro Shindo

An optical system and pick-up device having an optical magnification suitable for three different optical disc formats and a light emitting means for emitting a laser beam having a wavelength corresponding to each disc in the optical system of the optical pickup for recording and/or reproducing an information signal to the optical discs. The optical pickup device has a first light emitting unit for emitting a laser beam having a first wavelength or a second wavelength, a second light emitting unit for emitting a laser beam having a third wavelength, a first collimator lens for transmitting the laser beams having the first or second wavelengths, a second collimator lens for transmitting the laser beam having the third wavelength, a first objective lens for transmitting the laser beams having the first or third wavelengths, and a second objective lens for transmitting the laser beam having the second wavelength.

Optical pickup device, recorder and/or reproducer

The astigmatic aberration in an optical system is to be adjusted. Specifically, in an optical disc device on which can be selectively loaded a first optical disc having a first index of double refraction or a second optical disc having a second index of double refraction larger than said first index of double refraction, and which includes a liquid crystal devicebetween a light sourceand an objective lensconverging a light beam radiated from said light source on the optical discloaded on the optical disc device, the voltage applied to the liquid crystal deviceis adjusted to correct the coma aberration or the astigmatic aberration for the first disc or the second disc, respectively.

Optical disc recording and/or reproducing apparatus and aberration adjustment method

The present invention is capable of selectively reproducing an information signal from an optical disk with any of a plurality of types having different track pitches of recording tracks, that is, capable of selectively reproducing an information signal from an optical disk having a low or high recording density by determining the type of the optical disk, that is, determining whether a mounted optical disk is a low-recording-density optical disk or a high-recording-density optical disk. The present invention deliberately generates aberration in an optical beam by controlling a voltage applied to a liquid-crystal device in order to vary the diameter of the optical beam in accordance with the determined type of the optical disk. The present invention is thus characterized in that it is applicable to an optical pickup apparatus for changing the diameter of an optical beam in accordance with whether a mounted optical disk is a low-recording-density optical disk or a high-recording-density optical disk, as well as applicable to an optical-disk reproducing apparatus and an optical-disk recording & reproducing apparatus that employ the optical pickup apparatus.

Optical-disk reproducing apparatus, optical pickup apparatus and optical-disk recording and reproducing apparatus

An objective lens driving device employed in an optical pickup device of a recording and/or reproducing apparatus for an optical disk adapted to perform recording and/or reproduction of data signals on or from an optical disk as a recording medium includes an objective lens bobbin mounting an objective lens, objective lens supporting members for movably supporting the objective lens bobbin in the focusing direction and in the tracking direction, and an electromagnetic driving unit for driving the objective lens in the focusing and tracking directions simultaneously with the focusing coils and the tracking coils wound about the objective lens bobbin. The objective lens supporting member is formed by bending a single spring plate in the form of a rectangular frame and includes a pair of supporting arm sections extending parallel to each other, a pair of connecting plate sections interconnecting both ends of these supporting arm sections and resilient deflective sections formed in the connecting plate sections. These resilient deflective sections may be resiliently deflected in the direction at right angles with the deflection along the direction of thickness of the supporting arm sections, which direction is the direction of thickness of the connecting plate sections.

Objective lens driving device

A tracking control apparatus for use with an optical recording/reproducing apparatus includes a stationary optical section provided with a laser light source, a movable optical section provided with an objective lens by means of which three laser beams emanating from the laser light source are directed onto an optical disk, and a plurality of photodetectors having light receiving surfaces each divided into at least two segments adapted to receive the three reflected laser beams from the optical disk. A tracking control signal computing device taken the difference of detection outputs from the light receiving surfaces of said photodetectors to produce plural tracking error signals and divides the tracking error signals by the total light quantities received by the photodetectors for normalizing the tracking error signals to derive a tracking signal.

Tracking apparatus having movable and stationary parts

Apparatus for recording and reproducing information in record tracks on a rotatable record disc comprises a disc driving portion for rotating the rotatable record disc about an axis of rotation, a pair of optical heads each facing the rotatable record disc and respectively positioned on opposite sides of the axis of rotation, and a head driving portion for moving the optical heads simultaneously towards or away from each other in a radial direction on the rotatable record disc. Each optical head generates a first light beam used selectively for erasing and writing an information signal in the record track and a second light beam used for reading an information signal from the record track and causes the first and second light beams to impinge upon the record track on the rotatable record disc in such a manner that the first light beam precedes the second light beam in a direction along the record track.

Growing community of inventors

Kanagawa, Japan

Yuhei Kobayashi