Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Masaki Taniguchi

Hiroshi Yamaguchi

Hideo Fukuda

Yuzo Shimizu

Takaki Iwai

Hisatada Yasukawa

Yasufumi Shirakawa

Shinya Esaki

Yousuke Kuroiwa

Tetsuo Chato

Masaya Ueda

Ryoichi Ito

Ryouichi Ito

Yasushi Jin

An optical semiconductor device includes a phototransistor for receiving incident light. The phototransistor includes a collector layer of a first conductivity type formed on a semiconductor substrate, a base layer of a second conductivity type formed on the collector layer, and an emitter layer of a first conductivity type formed on the base layer. A thickness of the emitter layer is equal to or less than an absorption length of the incident light in the semiconductor substrate.

Optical semiconductor device

A packaging structure suitable for an integrated circuit device receiving short-wavelength laser light is provided. A lead-mounted substrate is placed on the side of the light receiving surface of the integrated circuit device having a photo detecting part. The lead is electrically connected with the integrated circuit device via an electrode. The integrated circuit device and the substrate are encapsulated with an encapsulation section. The substrate has an opening at a position above the photo detecting part.

Integrated circuit device packaging structure and packaging method

A transistor that forms an integrated circuit, a photo detector and a micromirror are mounted on the same semiconductor substrate in an optical semiconductor device of the present invention, which has an antireflection film that is formed on the photo detector, a first insulating film which is formed on the antireflection film and in which an opening is created in the state where the antireflection film is exposed, and an etching stopping film which is formed on the first insulating film and which has been left in the periphery around the opening in the first insulating film on the antireflection film and in the periphery around the portion above the micromirror.

Optical semiconductor device and manufacturing method for same

A photo detector IC (PDIC) is connected with a flexible printed circuit board (FPC). A signal converted into a voltage through light-to-voltage conversion in the PDIC is connected with the drain of a field effect transistor (FET), while the source of the FET is connected to an output terminal. A signal from the output terminal is input into a signal processing board of the main body via the FPC serving as an equivalent circuit composed of a coil and a capacitor. The gate of the FET is connected with a variable voltage source. Peaking occurs due to inductor components and capacitance components of the FPC. However, by application of voltage to the variable voltage source, the gate voltage value of the FET is adjusted to be an optimal value, whereby the peaking is suppressed by the on-resistance of the FET.

Output impedance varying circuit

The test circuit according to the present invention includes: a plurality of light-receiving elements; a plurality of amplifiers, each of which converts, into a voltage, a photoelectric current supplied from one of the light-receiving elements; and an electric current supplying unit which supplies an electric current to each of the light-receiving elements and each of the amplifiers. In this test circuit, the electric current supplying unit selectively supplies an electric current to a first group of light-receiving elements and to a second group of light-receiving elements, the first group of light-receiving elements including light-receiving elements, out of the plurality of light-receiving elements, which are neither vertically nor horizontally adjacent to each other, and the second group of light-receiving elements including light-receiving elements, out of the plurality of light-receiving elements, which are vertically or horizontally adjacent to the light-receiving elements of the first group of light-receiving elements.

Test circuit and test method that includes supplying a current to a plurality of light-receiving elements

An operational amplifier including a pair of differential input transistors is provided with a feedback resistor switching circuit and a variable current source. When a loaded optical disk is a DVD-ROM, the feedback resistor switching circuit reduces a gain of the operational amplifier and the variable current source selects a large current (of, for example, 1 mA) as a common bias current supplied to the differential input transistors. When the loaded optical disk is a DVD-RAM with low reflectance and low recording/reproducing speed, the feedback resistor switching circuit enhances the gain of the operational amplifier and the variable current source selects a small current (of, for example, 0.5 mA) as the common bias current.

Amplifier circuit for optical disk drive

An amplifier unit is provided, with which the need for manufacturing a photoelectric conversion IC in Bi-CMOS process is eliminated, and relatively low process cost of the photoelectric conversion IC is achieved. The input section of a buffer (the base of a transistor Q) is connected with a plurality of patterns of phase compensation circuits each including a resistor and a capacitor connected in series. A bipolar transistor (Q) is interposed between a positive power supply line and a capacitor (C) forming a capacitance of the phase compensation circuit. By switching on/off the bipolar transistor (Q), the capacitance value and resistance value of the phase compensation circuit are switched. Since the bipolar transistor (Q) is interposed between the capacitor (C) and the positive power supply line, base current (Isw) acting as a switch signal does not affect the amplifier unit.

Amplifier unit and optical disc drive

A semiconductor photodetector device includes: a first semiconductor layer of a first conductivity type; and a second semiconductor layer of a second conductivity type formed on the first semiconductor layer and having a light-receiving region. The first semiconductor layer includes a first region containing an impurity of the first conductivity type at a high concentration and a second region formed on the first region and containing an impurity of the first conductivity type at a concentration lower than that of the first region. The second semiconductor layer includes a third region containing an impurity of the second conductivity type at a concentration higher than that of the second region and a fourth region formed on the third region and containing an impurity of the second conductivity type at a concentration higher than that of the third region.

Semiconductor photodetector device

A packaging structure suitable for an integrated circuit device receiving short-wavelength laser light is provided. The integrated circuit device having a photo detecting part, leads and wires for connection therebetween are encapsulated in an encapsulation section. A recess is formed on the light incident surface of the encapsulation section above the photo detecting part, to thin the encapsulation section on the surface of the photo detecting part and thereby reduce the energy of light absorbed by the encapsulation section.

Growing community of inventors

Kyoto, Japan

Masaki Taniguchi