Matsushita Electric Industrial Co., Ltd.

Matsushita Electronics Corporation

Matsushita Electronics Company

Akio Yoshikawa

Hideyuki Nakanishi

Shinichi Ijima

Shoichi Takasuka

Hideo Nagai

Akira Ueno

Naoki Nakanishi

Masaaki Yuri

Teruhiro Shiono

Toru Takayama

Kazutoshi Onozawa

Kazuhiko Yamanaka

Masahiro Kume

Hirokazu Shimizu

Takashi Sugino

Toshiya Fukuhisa

Shin'ichi Ijima

Yoshiaki Komma

Osamu Imafuji

Ryuma Hirano

Yasuyuki Kochi

Masaya Manno

Yasuyuki Kouchi

Hisanori Ishiguro

Syouichi Takasuka

Shin-ichi Ijima

Shouichi Takasuka

An optoelectronic device that provides an excellent reproduction signal and a stable servo control while preventing deterioration of S/N ratio caused by stray light. The optoelectronic device has a semiconductor laser () that emits light beams on an information-recording medium (), a hologram optical element () having a diffraction grating region () and located between the semiconductor laser () and the information-recording medium (), and a photodetector () for receiving light that is diffracted at the diffraction grating region () of the hologram optical element (), among returning light beams from the information-recording medium (), and the optoelectronic device has also a diffraction grating region () in the vicinity of the diffraction grating region () of the hologram optical element () so as to prevent stray light other than diffracted light from the diffraction grating region () from entering the photodetector ().

Optoelectronic device

A first diffractive optical element pattern with a pattern pitch that is no greater than a wavelength of incident light is formed on a first main surface of substrate such as a glass plate. Second diffractive optical element patterns are formed at positions that are respectively incident to positive first-order diffracted light and negative first-order diffracted light produced by the first diffractive optical element pattern. Negative first-order diffracted light produced by each second diffractive optical element pattern is incident upon a boundary face of the substrate at an angle that is smaller than the critical angle, and so exits the substrate.

Diffractive optical element that polarizes light and an optical pickup using the same

A semiconductor laser, including: an n-type cladding layer that has n-type conductivity; an active layer formed on top of the n-type cladding layer; a p-type cladding base layer that is formed on top of the active layer and has p-type conductivity; a current-blocking layer that is formed on specified parts of an upper surface of the p-type cladding base layer and substantially has n-type conductivity; and a p-type buried cladding layer that has p-type conductivity and is formed so as to cover the current-blocking layer and contact remaining parts of the upper surface of the p-type cladding base layer. The current-blocking layer has at least two regions having different concentrations (hereafter &ldquo;N1&rdquo; and &ldquo;N2&rdquo; where N1<N2) of n-type carriers, a region adjacent to an interface between the p-type cladding base layer and the p-type buried cladding layer having the N1 concentration of n-type carriers and a part or, all of a remaining region of the current-blocking layer region having the N2 concentration.

Semiconductor laser and a manufacturing method for the same

A movable enclosure contains optical components, such as an objective lens, a semiconductor laser, a mirror, and a photodetector. The movable enclosure is supported by a fixed member via a plurality of wires that are positioned in parallel. This construction allows the movable enclosure to move in a tracking direction and a focusing direction. The plurality of wires are insulated from one another to be also used as power-supplying lines and signal lines for the semiconductor laser and the photodetector.

Optical pickup with improved optical properties

An optical device includes a light-emitting element for irradiating light onto an information recording medium, a diffraction grating for splitting light emitted from said light-emitting element into a plurality of beams, a focussing member for focussing the plurality of beams onto the information recording medium, a deflection member for deflecting the plurality of beams after they have been reflected from the information recording medium; and a photodetector for receiving the plurality of beams after they have been deflected by the deflection member. The diffraction grating has a first grating region and a second grating region, which have different diffraction efficiencies. The zero-order diffraction light in the first grating region is used as the main beam for reproducing the information signal, and the &plus;1-order or &minus;1-order diffraction light in the second grating regions is used as sub-beams for reproduction of the tracking error signal. Thus, the light amount of both the main beam and the sub-beams can be increased without increasing the light emission of the semiconductor laser element , and the S/N ratio of the main beam and the sub-beams can be enhanced.

Optical device with diffraction grating having plural grating regions

A semiconductor laser, includes: a first cladding layer; an active layer that is formed on top of the first cladding layer; a second cladding layer that is formed on top of the active layer and has a different type of conductivity to the first cladding layer; an etch-stop layer that is formed on top of the second cladding layer and has a same type of conductivity as the second cladding layer; and a light-confining construction that is formed on top of the etch-stop layer by an etching process. The etch-stop layer has a surface part that contacts the light-confining construction. This surface part is composed of an (Al Ga ) In P semiconductor, where 0.2&lE;x<0.7 and 0<y&lE;1.

A semiconductor laser device includes a semiconductor laser element, a light beam branching element for branching a light beam emitted from the semiconductor laser element and reflected by an optical recording medium into a plurality of light beams, a light beam reflector for reflecting the light beam branched by the light beam branching element, and a photodetector portion for detecting the light beam reflected by the light beam reflector. The light beam branching element and the photodetector portion are formed on the same substrate. The miniature semiconductor laser device can be assembled without complicated position adjustment and has less deterioration of characteristics arising from misregistration during and after assembly.

Semiconductor laser device

An optical pickup that is equipped with a photodetector unit, irradiates an optical disc with a laser beam, and receives returning light reflected by the optical disc, where the optical pickup is constructed to (1) divide the laser beam into a main beam, a preceding sub-beam, and a succeeding sub-beam, (2) direct the main beam, the preceding sub-beam, and the succeeding sub-beam toward the optical disc, and (3) divide returning lights of the main beam, the preceding sub-beam, and the succeeding sub-beam respectively into first-fourth main returning lights, first-fourth preceding returning lights, and first-fourth succeeding returning lights, and the photodetector unit includes: first-fourth main photodetectors that respectively receive the first-fourth main returning lights; first-fourth preceding photodetectors that respectively receive the first-fourth preceding returning lights; and first-fourth succeeding photodetectors that respectively receive the first-fourth succeeding returning lights. A tracking error signal appropriate to the optical disc to be reproduced is selected from three tracking error signals detected according to the detection signals from the photodetectors, and a tracking servo is driven according to the selected tracking error signal.

Photodetector unit, and optical pickup, optical reproduction apparatus, and optical recording apparatus equipped with the same

A semiconductor light-emitting unit includes: a semiconductor laser diode; a photodetector functioning as a sub-mount for mounting the diode thereon; and a heating member, incorporated with the photodetector, for heating the diode. If the ambient temperature of the diode falls within a range where kinks are possibly caused in the low-temperature I-L characteristic of the diode, then current is supplied to the heating member, thereby heating the diode. The heating member may be either a doped region defined within a semiconductor substrate or a doped polysilicon film formed on the substrate. Also, the heating member is preferably located under the laser diode with a heat-dissipating layer and an insulating layer interposed therebetween. The semiconductor light-emitting unit with this structure can effectively eliminate kinks from the low-temperature I-L characteristic of the semiconductor laser diode.

Semiconductor light-emitting unit, optical apparatus and optical disk system having heat sinking means and a heating element incorporated with the mounting system

A lead frame includes a die pad including a die pad main portion having a large thickness and a die pad peripheral portion having an intermediate thickness smaller than that of the die pad main portion, provided on at least one side of the die pad main portion, at least one support lead connected to the die pad, and at least two first inner leads having a small thickness smaller than that of the die pad peripheral portion, arranged such that end portions thereof are opposed to the die pad peripheral portion. The thick die pad provides good heat release properties, and reducing the thickness of the leads allows fine pitched leads to be produced. Such a lead frame can be manufactured easily by press stamping after belt-shaped regions having different thickness are formed by rolling.

Lead frame which includes a die pad, a support lead, and inner leads

An optical device includes a light-emitting element for irradiating light onto an information recording medium, a diffraction grating for splitting light emitted from said light-emitting element into a plurality of beams, a focussing member for focussing the plurality of beams onto the information recording medium, a deflection member for deflecting the plurality of beams after they have been reflected from the information recording medium; and a photodetector for receiving the plurality of beams after they have been deflected by the deflection member. The diffraction grating has a first grating region and a second grating region, which have different diffraction efficiencies. The zero-order diffraction light in the first grating region is used as the main beam for reproducing the information signal, and the &plus;1-order or &minus;1-order diffraction light in the second grating regions is used as sub-beams for reproduction of the tracking error signal. Thus, the light amount of both the main beam and the sub-beams can be increased without increasing the light emission of the semiconductor laser element and the S/N ratio of the main beam and the sub-beams can be enhanced.

Method for manufacturing an optical pickup

A semiconductor laser device of the present invention includes: a semiconductor laser chip including an anode and a cathode; and a field effect transistor. The anode of the semiconductor laser chip is connected to the drain of the field effect transistor. The gate of the field effect transistor is connected to the drain of the field effect transistor. And the cathode of the semiconductor laser chip is connected to the source of the field effect transistor.

A semiconductor laser device includes a semiconductor laser element for emitting laser light onto a recording medium; beam dividing element provided in an optical path between the semiconductor laser element and the recording medium; a hologram optical element including a diffraction grating formed in a light-transmitting substrate, the hologram optical element located in an optical path between the beam dividing element and the semiconductor laser element; a servo-signal light-receiving element provided in an optical path of diffracted light transmitted through the diffraction grating for receiving the diffracted light; an information-signal light-receiving element for receiving light divided by the beam-dividing element, which is different from light divided by the beam-dividing element which is received by the diffraction grating; and a polarizing element provided in an optical path between the beam dividing element and the information-signal light-receiving element, wherein the semiconductor laser element, the servo-signal light-receiving element and the information-signal light-receiving element are provided within a single package, and the information-signal light-receiving element is provided outside an optical path of every order of diffracted light transmitted through the diffraction grating.

Growing community of inventors

Kyoto, Japan

Akio Yoshikawa