Sharp Kabushiki Kaisha Corporation

Toshiharu Inui

Tomoyuki Miyake

Yoshihiro Sekimoto

Nobuo Ogata

Yasuo Nakata

Kunio Kojima

Jun Akiyama

Hideaki Sato

Akira Takahashi

Shigemi Maeda

Toshiyuki Tanaka

Hideharu Tajima

Hiroshi Fuji

Hideaki Fujita

Nobuyuki Takamori

Toshihiro Tamura

Masayuki Nishikawa

Mitsunobu Yoshida

Nobuyuki Usui

Takashi Kawano

Shinichi Tomoyama

One end of an FPC () for supplying power to the driving section of a light amount control section provided in a shutter unit () is disposed between a second lens holder () and the shutter unit () secured to this second lens holder () and is held between the second lens holder () and the shutter unit (). Thus, the FPC () is prevented from being spaced apart from the shutter unit (), and a member for securing the FPC () to the shutter unit () is eliminated, reducing the number of part items. Further, the second lens holder () and the shutter unit () blocks unwanted light toward the FPC (), so that a ghost image is prevented from appearing on an image due to unwanted light reflected on the FPC ().

Lens unit

An objective lens holder of the present invention includes: (i) a cavity, having an entrance and an exit, which guides, to an objective lens, an incident light beam entering the entrance, the exit being provided on a side of the cavity where the objective lens is housed; and (ii) an aperture having an opening for limiting, to an effective diameter of the objective lens, a beam diameter of the incident light beam passing through the cavity. The cavity is surrounded with internal wall surfaces facing each other so that space between the internal wall surfaces gradually increases from the opening of the aperture toward the entrance or the exit. This makes it possible to provide a highly rigid objective lens holder that allows high speed read/write operations.

Objective lens holder, objective lens driving device including same and optical disk read/write device

An objective lens driving device includes: a movable sectionfor collecting light of a light source onto an optical disk; and a driving section for driving the movable section(i) in a direction of a light axis of an objective lenswhich direction is orthogonal to a storage surface of the optical diskand (ii) in an in-plane direction orthogonal to the light axis, wherein the movable sectionincludes a protruding portionwhich protrudes in a direction orthogonal to the direction of the light axis of the objective lens, and there is provided a stopper sectionfor restricting a movable range of the movable sectionby coming into contact with the protruding portionwhen the movable sectionmoves.

Objective lens driving device and optical pickup device using the same

A disk cartridge having a small size and a sufficient portability. The disk cartridge has a size of 58 mm (L)&#xd7;54 mm (L)&#xd7;4 mm (L), a thickness less than 5 mm and a small area less than a square of 65 mm. The disk cartridge has a notch 10 formed on the insertion side and having a width of 2 mm (L) and a length of 27.5 mm (i.e., a taper portion of 6 mm (L)+a straight portion of 21.5 mm (L)).

Disk cartridge

A reproducing light quantity control method for an optical memory device includes the steps of (1) recording test data on an optical recording medium; (2) reproducing the test data recorded on the optical recording medium by changing a reproducing light quantity in a plurality of light quantity values; (3) measuring a quality value and a signal quantity of each of a plurality of reproducing signals from the test data; (4) selecting an optimum reproducing signal quantity from a plurality of reproducing signal quantities in accordance with quality values of the plurality of reproducing signals so as to decide a target value of reproducing signal quantity; and (5) recording the target value on a target value recording region of the optical recording medium. This method reduces the time required to obtain a target value of a reproducing signal quantity and speeds up an operation from installing of the optical recording medium to finishing of preparation for recording and reproducing.

Reproducing light quantity control method for optical memory device, and reproducing light quantity control device, and optical recording medium

An information recording-reproduction method wherein: upon reproducing, recorded information corresponding to a predetermined number of sectors from the leading sector of each of a plurality of information tracks on an optical disk is preliminarily stored on a buffer memory, and during a period in which the optical pickup is shifted to another information track, the recording information, stored in the buffer memory, is reproduced; and upon recording, during a period in which the optical pickup is shifted to another information track, recording information is temporarily stored in the buffer memory, and after completion of the recording, the recording information is recorded on the optical disk. In this method, information tracks, which are formed on the optical disk discontinuously with one .another, are regarded as if they were continuous tracks, and the apparent recording and reproducing operation is carried out continuously.

Information recording-reproduction method

A magneto-optical recording and reproducing apparatus includes a magnetic head for modulating a magnetic field according to a recording signal. There are three separate coils around a single magnetic core the magnetic head. Three coil driving circuits are included, each one associated with a separate coil for switching the direction of magnetic field generated by said separate coils. A selecting circuit is used for starting or stopping the transmission of the recording signal to the coil driving circuits.

Multiple coil magnetic head for magnetic optical recording device

In an objective lens driving apparatus used in an optical information recording and reproducing apparatus or the like, a vibration is suppressed and a resonance peak on transfer function is suppressed when movable portions are moved in focusing and tracking directions and when these portions are turned around focusing and tracking directions. An elastic body which supports the movable portions movably in two directions, i.e., focusing direction and tracking direction to a fixed portion includes a bent portion in an intermediate portion between the side of movable portion and the side of fixed portion. A damper member is adhered to bridge a gap between a branched arm portion branching from a linear portion extending from the side of movable portion, and a fixed portion. The bent portion couples two linear portions and which are not on the same line.

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Yamatokoriyama, Japan

Toshiharu Inui