Abstract: A high-reliability power semiconductor device uses a lead-free solder layer to connect a semiconductor chip such as an IGBT to an insulating substrate having a ceramic board and conductor layers, and a lead-free solder layer to connect the insulating substrate to a radiating base. Before the insulating substrate and the radiating base are solder-connected, the radiating base is warped such that the surface of the radiating base on the side opposite to the insulating substrate is convex. The insulating substrate is solder-connected onto the warped radiating base with the lead-free solder so as to provide a substantially flat solder-connected radiating base. When the radiating base is attached to a cooling fin, the thermal resistances are lower, and heat from the semiconductor chip is effectively dissipated so as to prevent abnormal temperature rise.

Abstract: In this optical scanning device, a plurality of scanning optical systems are arranged in a main scanning direction. Each of the scanning optical systems includes a deflecting unit performing an optical scanning by oscillation. Scanning frequencies of the deflecting units are substantially equal to one another. Each of the deflecting units is provided with means for varying the scanning frequency. The scanning frequency of each of the deflecting units is set midway between a maximum value and a minimum value of a resonance frequency intrinsic to the deflecting unit.

Abstract: A semiconductor device includes a circuit board formed of an insulator substrate and having conductor patterns on both surfaces thereof, a semiconductor chip bonded to the circuit board with one of the conductor patterns therebetween, and a radiator base bonded to the circuit board with a solder layer through the other of the conductor patterns therebetween for conducting heat generated in the semiconductor chip to an outside device. The radiator base is formed of a material having anisotropic thermal conductivity so that the radiator base has thermal conductivity in a direction perpendicular to a bonding plane between the radiator base and the circuit board higher than that along the bonding plane. The radiator base has thermal expansion coefficient along a bonding plane with the circuit board different from that along the bonding plate of the insulator substrate by a predetermined value.

Abstract: An optical scanning apparatus includes a vibration mirror having a mirror surface that reflects an optical beam. A pair of torsion beams swingably support the mirror. The mirror is vibrated in a sealed space whose pressure is adjusted such that a characteristic of the mirror falls within a predetermined range.

Abstract: A power semiconductor module and a method of manufacture thereof includes lead a frame carrying lead having inner and outer lead portions. The outer lead portions, which are connected by soldering to semiconductor chips simultaneously, eliminate the need for using bonding wires. Since no bonding wire is used for connecting the leads and the semiconductor chips, a sufficient current capacity is obtained. The bonding between an insulating circuit board and the semiconductor chips and the bonding between the semiconductor chips and the leads can be made simultaneously in a single step of reflow-soldering. As a result, the mounting time can be shortened and the power semiconductor module can be manufactured more efficiently.

Abstract: A semiconductor device includes a package composed of a metal base, an enclosure case integrated with terminals, and a top cover. A power circuit and a control circuit are arranged inside the package vertically, and a gel-like filler is injected to seal the package after being assembled. In this semiconductor device, externally lead control terminals for the control circuit are insert-molded in a control terminal block constituting an independent component. The control terminal block is fixed to the enclosure case to extend over a center of a top surface thereof. A printed circuit board of the control circuit is disposed and connected between the control terminal block and a relay terminal block disposed inside the case.

Abstract: A deflector mirror is disclosed that includes a mirror substrate configured to vibrate in a reciprocating manner on beams as a torsional rotary shaft so as to deflect a light beam emitted from a light source. The mirror substrate includes multiple regions in each of portions thereof extending from the torsional rotary shaft to respective ends of the mirror substrate, the regions being different in flexural rigidity.

Abstract: An optical scanning device is disclosed that is manufactured through a simple mounting process and is provided with a hermetically sealed oscillation space for an oscillation mirror. The optical scanning device includes plural drive electrodes for driving the oscillation mirror and plural external electrodes of the drive electrodes that are formed at the same height.

Abstract: A method of manufacturing a semiconductor device is disclosed in which a metallic deposit is stably formed on the anode side with small variation in film thickness, and plating is prevented on the cathode side without carrying out any additional processing on the cathode side. The processed anode side causes no interference in subsequent processing. Insulator films are used to cover a scribe line, as well as a field plate or an open electrode provided on a surface of a silicon substrate before Ni electroless plating of an aluminum electrode is performed to form a metallic deposit on the electrode.

Abstract: A semiconductor device can be formed with fewer voids in the solder bonding a laminate of a silicon chip, an insulator substrate, and a metal base, with a solder layer positioned between the layers. After placing the laminate in a furnace, it is evacuated and then pressurized with hydrogen gas, and then heated to melt the solder. While maintaining the heat, the furnace is again evacuated to remove voids in the solder, and then the furnace is positively pressurized again with hydrogen gas to prevent holes produced by the voids traveling in the solder, and to obtain a uniform solder fillet shape. Thereafter the laminate is rapidly cooled to obtain a finer grain solder to increase the rate of creep to quickly remove the warping of the laminate to the original state.

Abstract: An optical scanning apparatus includes a vibration mirror having a mirror surface that reflects an optical beam. A pair of torsion beams swingably support the mirror. The mirror is vibrated in a sealed space whose pressure is adjusted such that a characteristic of the mirror falls within a predetermined range.

Abstract: A semiconductor device includes a circuit board formed of an insulator substrate and having conductor patterns on both surfaces thereof, a semiconductor chip bonded to the circuit board with one of the conductor patterns therebetween, and a radiator base bonded to the circuit board with a solder layer through the other of the conductor patterns therebetween for conducting heat generated in the semiconductor chip to an outside device. The radiator base is formed of a material having anisotropic thermal conductivity so that the radiator base has thermal conductivity in a direction perpendicular to a bonding plane between the radiator base and the circuit board higher than that along the bonding plane. The radiator base has thermal expansion coefficient along a bonding plane with the circuit board different from that along the bonding plate of the insulator substrate by a predetermined value.

Abstract: A semiconductor device can be formed with fewer voids in the solder bonding a laminate of a silicon chip, an insulator substrate, and a metal base, with a solder layer positioned between the layers. After placing the laminate in a furnace, it is evacuated and then pressurized with hydrogen gas, and then heated to melt the solder. While maintaining the heat, the furnace is again evacuated to remove voids in the solder, and then the furnace is positively pressurized again with hydrogen gas to prevent holes produced by the voids traveling in the solder, and to obtain a uniform solder fillet shape. Thereafter the laminate is rapidly cooled to obtain a finer grain solder to increase the rate of creep to quickly remove the warping of the laminate to the original state.

Abstract: An optical deflecting unit includes a torsion mirror which is pivotable about an axis and has a deflecting reflection surface which receives a light beam at an incident angle inclined with respect to a plane which is perpendicular to the axis and the deflecting reflection surface, and at least one fixed mirror surface confronting the torsion mirror and arranged so that the light beam is reflected between the torsion mirror and the at least one fixed mirror surface a plurality of times. A moving direction of a reflection position of the light beam on the torsion mirror in a sub scan direction reverses.

Abstract: In this optical scanning device, a plurality of scanning optical systems are arranged in a main scanning direction. Each of the scanning optical systems includes a deflecting unit performing an optical scanning by oscillation. Scanning frequencies of the deflecting units are substantially equal to one another. Each of the deflecting units is provided with means for varying the scanning frequency. The scanning frequency of each of the deflecting units is set midway between a maximum value and a minimum value of a resonance frequency intrinsic to the deflecting unit.

Abstract: An optical deflector of the present invention includes a movable mirror and torsion bars supporting the mirror and formed integrally with the mirror. The mirror reciprocatingly vibrates to reflect a light beam to thereby deflect it. The mirror is curved in the form of an arch in a section including at least the torsion bars. The mirror deforms little during vibration even if it is thin. Small power can cause such a thin mirror to vibrate with a large amplitude.

Abstract: A semiconductor device includes a package composed of a metal base, an enclosure case integrated with terminals, and a top cover. A power circuit and a control circuit are arranged inside the package vertically, and a gel-like filler is injected to seal the package after being assembled. In this semiconductor device, externally lead control terminals for the control circuit are insert-molded in a control terminal block constituting an independent component. The control terminal block is fixed to the enclosure case to extend over a center of a top surface thereof. A printed circuit board of the control circuit is disposed and connected between the control terminal block and a relay terminal block disposed inside the case.

Abstract: An ink jet head that can be easily connected to an external circuit is provided without an increase in the number of production procedures. Diaphragms and a diaphragm external electrode having the same thickness as the diaphragms are formed on a silicon substrate that is a first substrate located on the same plane as the diaphragms. The diaphragm external electrode is located within 2 &mgr;m from the individual external electrodes of a plurality of electrodes on a second substrate.

Abstract: An optical deflecting unit includes a torsion mirror which is pivotable about an axis and has a deflecting reflection surface which receives a light beam at an incident angle inclined with respect to a plane which is perpendicular to the axis and the deflecting reflection surface, and at least one fixed mirror surface confronting the torsion mirror and arranged so that the light beam is reflected between the torsion mirror and the at least one fixed mirror surface a plurality of times. A moving direction of a reflection position of the light beam on the torsion mirror in a sub scan direction reverses.