Abstract: An optical element mounted on a wiring board is sealed by a sealing resin except an optical function region. Wires connecting the wiring board with the optical element are also sealed by the sealing resin. The optical function region is exposed as a bottom surface of a recess whose side surface is formed by the sealing resin. The recess has a two-level structure of a bottom recess and a portion located over the bottom recess. A stepped portion extends from an upper end of a first side surface of the bottom recess to a lower end of a second side surface of the bottom recess.

Abstract: An electric device having high reliability is to be produced. An adhesive layer includes a thermosetting resin and a radiation-curable resin, and a portion of the adhesive layer is protruded outwardly from an edge of the electric part. Radiation rays do not pass through the electric part, and the radiation-curable resin is cured in the protruding portion, while the radiation-curable resin in that portion of the adhesive layer which is positioned right behind the electric part is not polymerized. Since the electric part is fixed with the polymerized radiation-curable type resin, the electric part is not misaligned when the electric part is pressed under heating.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A connecting part for ensuring a secure connection includes first connecting terminals that are arranged on one face of a supporting member and second connecting terminals that are arranged on the back face of the supporting member. The supporting member may have an elastic body. The connecting terminals are interconnected by conductive films which are formed on the face of the supporting member. Connecting parts are arranged between circuit boards on which electronic parts are mounted, and the circuit boards are mutually fixed in the state in which the connecting parts are compressed. The first and second connecting terminals are pushed against lands on the circuit boards by restoring force of the connecting parts, and then the circuit boards are electrically interconnected.

Abstract: 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 Q5) is connected with a plurality of patterns of phase compensation circuits each including a resistor and a capacitor connected in series. A bipolar transistor (Q6) is interposed between a positive power supply line and a capacitor (C2) forming a capacitance of the phase compensation circuit. By switching on/off the bipolar transistor (Q6), the capacitance value and resistance value of the phase compensation circuit are switched. Since the bipolar transistor (Q6) is interposed between the capacitor (C2) and the positive power supply line, base current (Isw) acting as a switch signal does not affect the amplifier unit.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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 Q5) is connected with a plurality of patterns of phase compensation circuits each including a resistor and a capacitor connected in series. A bipolar transistor (Q6) is interposed between a positive power supply line and a capacitor (C2) forming a capacitance of the phase compensation circuit. By switching on/off the bipolar transistor (Q6), the capacitance value and resistance value of the phase compensation circuit are switched. Since the bipolar transistor (Q6) is interposed between the capacitor (C2) and the positive power supply line, base current (Isw) acting as a switch signal does not affect the amplifier unit.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An optical integrated device includes a light source, a light-receiving element, a signal processing section, and a sleep control circuit. The light source irradiates a light beam onto an optical recording medium. The light-receiving element receives a reflected light of the light beam from the optical recording medium and outputs an electrical signal according to the reflected light. The signal processing section performs predetermined processing on the electrical signal outputted from the light-receiving element. The sleep control circuit is connected to a terminal which outputs a signal indicating the operation voltage of the light source, and controls whether to put the signal processing section in an operation state or a low power consumption state based on the voltage at the terminal.

Abstract: 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.