Sharp Kabushiki Kaisha Corporation

Osamu Hamaoka

Takeshi Horiguchi

Ikuo Kohashi

Hiroshi Nakatsu

Shinzoh Murakami

Katsushige Masui

Takehiro Shiomoto

Akira Ariyoshi

Hisayuki Shinohara

Hideki Ichikawa

Takahide Ishiguro

Provided is an optical pickup apparatus that can be made compact and is capable of producing stable push-pull signals. The optical pickup apparatus includes a light source, an objective lens, a diffraction element, a light-receiving element, and a control-driving section. The diffraction element receives light reflected from an optical recording medium. The light-receiving element receives light beams diffracted by the diffraction element. The light-receiving element has a plurality of light-receiving regions. The light-receiving region produces an output signal responsive to the quantity of the incident light beam. The control-driving section obtains differences among the output signals from a plurality of the light-receiving regions by calculation to derive a push-pull signal, and drives the objective lens under control on the basis of the push-pull signal.

Optical pickup apparatus

A semiconductor laser chip is mounted on one surface of an electrode lead for chip mounting having a heat release region for releasing heat around the semiconductor laser chip. Therefore, it is possible to release heat of the semiconductor laser chip to the chip mounting lead and release the heat from the heat release region, thereby suppressing increase of a temperature of the semiconductor laser chip and suppressing shortening of life of the semiconductor laser chip.

Semiconductor laser device, method for manufacturing the same and optical pickup apparatus

A semiconductor laser device includes a one-body submount composed of a predetermined material such as SiC or AlN and placed on a mounting surface. A laser diode is placed on a front portion of an upper surface of the submount. A monitoring photodiode composed of crystalline silicon is stacked on a portion of the upper surface of the submount backward from the laser diode.

Semiconductor laser device

A semiconductor laser device has a semiconductor laser and a polarizing diffraction grating that is arranged ahead of the semiconductor laser. A reflected light from an optical recording medium is diffracted by the polarizing diffraction grating according to the polarization direction of the reflected light. The reflected light is thereby deviated from the direction toward the semiconductor laser to prevent the reflected light from returning to the semiconductor laser.

Semiconductor laser device and optical pickup device

An optical pickup comprises a light source, a three-way split light diffracting section for dividing light emitted from a light source into one main beam and two subbeams, a hologram for dividing each of the main beam and the subbeams reflected from a recording medium into two predetermined directions, and a light receiving section for receiving the beams divided by the hologram. The hologram includes two regions having a small-pitch grating for diffracting each beam to a predetermined direction, the small-pitch gratings have substantially the same pitch and are symmetrical about a split line separating the two regions.

Optical pickup system with light receiving portion

In a semiconductor laser device, a semiconductor laser chip is placed on a stem so that an end surface of the semiconductor laser chip, on which the main radiation side light emission point is located, protrudes from an edge of a header portion of the stem or from an edge of a header portion of a sub-mount provided on the stem so as to conceal no light emission points of the semiconductor. A conductive die bonding paste is used for the die bonding of the semiconductor laser chip. A chamfered portion or a rounded corner portion is formed at the edge of the header portion of the stem or the edge of the header portion of the sub-mount provided on the stem. Also, an optical pickup is constructed of at least the semiconductor laser device, a diffraction grating, a photodetector, a condenser lens and an object lens.

Semiconductor laser device, fabricating method thereof and optical pickup employing the semiconductor laser device

A semiconductor laser package includes an island member formed of metal, including a base plane and a block member protruding in a direction substantially perpendicular to the base plane, a lead, a resin member molded integrally with the island member and the lead so as to fix the relative position relationship between the island member and the lead, a laser chip fixed at the block member, and a light receiving element functioning as a light receiving unit, directly fixed to the resin member.

Growing community of inventors

Yamatotakada, Japan

Osamu Hamaoka