Abstract: No consideration is given to heat transferred from a semiconductor module to a capacitor via a bus bar module. The heat generated by a semiconductor module (1) is transferred to a bus bar module (3) via a DC terminal (1A) of the semiconductor module (1). As illustrated in FIG. 4(B), the heat transferred to the bus bar module 3 is then transferred to the pressing member 5 via the annular conductor 8 and the bolt 5A. Since the pressing member 5 is in close contact with the second cooler 2B, the heat transferred to the pressing member 5 is cooled by the second cooler 2B. On the other hand, the heat transferred to the convex portion 6A of the housing 6 is transferred to the first cooler 2A via the housing 6 and cooled. As a result, in the configuration in which a capacitor (4) is connected to the semiconductor module (1) via the bus bar module (3), the heat transferred from the semiconductor module (1) to the capacitor (4) can be suppressed.

Abstract: An electret includes a substrate and an electret layer formed above a surface of the substrate. The electret layer is a composite metal compound containing two or more different metal elements, and is obtained by subjecting a thin film mainly composed of an inorganic dielectric material having a bandgap energy of 4 eV or more to a polarization treatment.

Abstract: An electret includes an electret layer. The electret layer is formed by subjecting a composite film in which inorganic dielectric particles are dispersed and held in a base film to a polarization treatment. The inorganic dielectric particles are mainly composed of an inorganic dielectric material having a bandgap energy of 4 eV or more.

Abstract: An electret includes a composite oxide having an ABO3 type perovskite structure containing two different metal elements A and B. The composite oxide is in a polarized state, at least a part of one of the metal elements A and B is substituted with a dopant element having a lower valence than the one of the metal elements A and B, and the composite oxide has a bandgap energy of 4 eV or more.

Abstract: A power generator includes an electret including a first charged surface and a second charged surface having opposite polarities, a first electrode partially formed on the first charged surface, a second electrode formed on the second charged surface, a third electrode disposed to face the first charged surface with a space, and at least one of a power storage unit or an output unit. The first charged surface has a current collecting surface that is exposed outward. The first electrode and the second electrode form a first power generating unit and the third electrode and the second electrode form a second power generating unit. The electret is formed by polarizing an electret material that includes an inorganic dielectric having a bandgap energy of 4 eV or more.

Abstract: A power generator includes a power generating unit and at least one of a power storage unit or an output unit that is electrically connected to the power generating unit. The power generating unit includes an electret having a first charged surface and a second charged surface that are charged with opposite polarities, a first electrode formed on the first charged surface, and a second electrode formed on the second charged surface. The electret is formed by polarizing an electret material that includes an inorganic dielectric having a bandgap energy of 4 eV or more. At least one of the first electrode or the second electrode are partially disposed on the corresponding charged surface such that at least one of the first charged surface or the second charged surface has a portion as a current collecting surface exposed outward.

Abstract: An electret includes an electret layer. The electret layer is formed by subjecting a composite film in which inorganic dielectric particles are dispersed and held in a base film to a polarization treatment. The inorganic dielectric particles are mainly composed of an inorganic dielectric material having a bandgap energy of 4 eV or more.

Abstract: An electret includes a substrate and an electret layer formed above a surface of the substrate. The electret layer is a composite metal compound containing two or more different metal elements, and is obtained by subjecting a thin film mainly composed of an inorganic dielectric material having a bandgap energy of 4 eV or more to a polarization treatment.

Abstract: An electret includes a composite oxide having an ABO3 type perovskite structure containing two different metal elements A and B. The composite oxide is in a polarized state, at least a part of one of the metal elements A and B is substituted with a dopant element having a lower valence than the one of the metal elements A and B, and the composite oxide has a bandgap energy of 4 eV or more.

Abstract: A piezoelectric element includes a first electrode having a film shape and provided on a base portion, a second electrode having a film shape and opposed to the first electrode on an opposite side of the first electrode from the base portion, a piezoelectric film interposed between the first electrode and the second electrode and partially covered with the second electrode, and an insulation film covering the second electrode and the piezoelectric film with extending over at least a part of an outer edge of the second electrode. The insulation film may cover a whole of the outer edge of the second electrode without covering an inner region of the second electrode. Accordingly, a withstand voltage of the piezoelectric film can be increased.

Abstract: A piezoelectric element includes a substrate having a first surface with a predetermined orientation; a lower electrode layered on the first surface of the substrate; a piezoelectric thin film layered on the lower electrode and having a piezoelectric body; and an upper electrode layered on the piezoelectric thin film. A voltage is to be impressed between the lower electrode and the upper electrode to deform the piezoelectric thin film. The piezoelectric thin film is epitaxially grown on the lower electrode using a physical vapor deposition or a chemical vapor deposition.

Abstract: A piezoelectric element includes a first electrode having a film shape and provided on a base portion, a second electrode having a film shape and opposed to the first electrode on an opposite side of the first electrode from the base portion, a piezoelectric film interposed between the first electrode and the second electrode and partially covered with the second electrode, and an insulation film covering the second electrode and the piezoelectric film with extending over at least a part of an outer edge of the second electrode. The insulation film may cover a whole of the outer edge of the second electrode without covering an inner region of the second electrode. Accordingly, a withstand voltage of the piezoelectric film can be increased.

Abstract: A piezoelectric element includes a substrate having a first surface with a predetermined orientation; a lower electrode layered on the first surface of the substrate; a piezoelectric thin film layered on the lower electrode and having a piezoelectric body; and an upper electrode layered on the piezoelectric thin film. A voltage is to be impressed between the lower electrode and the upper electrode to deform the piezoelectric thin film. The piezoelectric thin film is epitaxially grown on the lower electrode using a physical vapor deposition or a chemical vapor deposition.

Abstract: A semiconductor laser structure includes: a plurality of laser structure units, wherein each laser structure unit includes a N conductive type clad layer, a light emission layer and a P conductive type clad layer, which are stacked in this order; and a tunnel junction layer disposed between two adjacent laser structure units. The tunnel junction layer includes a P conductive type layer and a N conductive type layer. The P conductive type layer includes a dopant of zinc. The N conductive type layer includes a dopant of a group six element.

Abstract: A radar apparatus has a light receiver that includes a refractive body and a mirror on an opposite surface of the refractive body relative to an incidence surface of the refractive body for receiving an incident light from an outside of the radar apparatus. The refractive angle of the refractive body is configured to be smaller than an incident angle of the incident light, and the mirror is configured to reflect at least a portion of the incident light toward a first light receiving element that is disposed on the incidence surface with its light receiving face facing the incidence surface of the refractive body.

Abstract: A radar apparatus has a light receiver that includes a refractive body and a mirror on an opposite surface of the refractive body relative to an incidence surface of the refractive body for receiving an incident light from an outside of the radar apparatus. The refractive angle of the refractive body is configured to be smaller than an incident angle of the incident light, and the mirror is configured to reflect at least a portion of the incident light toward a first light receiving element that is disposed on the incidence surface with its light receiving face facing the incidence surface of the refractive body.

Abstract: A high power stripe-geometry heterojunction laser diode device is provided which may be employed in a radar system designed to measure the distance to a target. The laser diode device has an electric circuit path extending from a first electrode connected to a voltage source to a second electrode connected to ground and features addition of a resistance of 1 m&OHgr; or more to the electric circuit path to provide uniform current distribution in an active layer for emitting a high density laser beam.

Abstract: A material and method for bonding a semiconductor device to a pedestal, which can obtain a sufficient bonding strength and stable electric contact, are disclosed. On an n-type electrode constituting an ohmic electrode for a semiconductor laser device are formed a Ni layer and an Au-Sn solder layer. Then, the solder layer is melted and bonded to a heat sink provided with Au-plating. The film thickness of the Ni layer is set to approximately 500 .ANG. or more. When the solder layer is melted, Ni in the Ni layer diffuses into the solder layer and Sn in the solder layer diffuses into the Ni layer. By this mutual diffusion, bonding strength and wettability between the semiconductor device and pedestal can be improved. In addition, by setting the composition ratio of Ni layer to the Au-Sn solder layer to 1.3 wt % or more and under 10 wt %, bonding can be performed at a lower melting point and concurrently a higher bonding strength can be obtained.

Abstract: The semiconductor laser device provides a large output laser beam approximating a circular shape. Formed on an n-GaAs substrate is an n-GaAs layer, further thereon in mesa type with an n-Al.sub.0.4 Ga.sub.0.6 As clad layer, an n-Al.sub.0.2 Ga.sub.0.8 As optical guide layer, an active layer formed of Al.sub.0.2 Ga.sub.0.8 As/GaAs multi-quantum well structure, a p-Al.sub.0.2 Ga.sub.0.8 As optical guide layer, a p-Al.sub.0.4 Ga.sub.0.6 As clad layer, and a p-GaAs layer. A thickness of the active layer is made equal to 127.5 nm, and a sum of thicknesses of the active layer and the optical guide layers and is made equal to or more than 1.5 .mu.m. On the n-GaAs layer and the upper surface of mesa shaped portion are formed an insulating film and a p-type electrode, the stripe width of which is equal to 400 .mu.m.