Abstract: A frame is made of a first material. An external terminal electrode is attached to the frame. A heat sink plate supports the frame and includes a mounting region in the frame. The heat sink plate is made of a non-composite material containing copper with purity of 95.0 weight percentage or more. A first adhesive layer bonds the frame and the heat sink plate to each other. The first adhesive layer is made of a second material different from the first material, and has a first composition. A power semiconductor element is mounted on the mounting region of the heat sink plate. A cover is attached to the frame to constitute a sealing space sealing the power semiconductor element without gross leak. A second adhesive layer bonds the frame and the cover to each other, and has a second composition different from the first composition of the first adhesive layer.

Abstract: Provided is a piezoelectric device which has high reliability for the joint between an external electrode and low-melting-point solder. This piezoelectric device is a fired body including a main body part and an external electrode. The external electrode includes a surface electrode that covers upper and lower surfaces of the main body part, and a side-surface electrode that covers a side surface of the main body part and makes a connection to the surface electrode. This piezoelectric device is obtained by co-firing all of constituent members. The surface electrode is configured to include platinum (Pt) or palladium (Pd). The side-surface electrode is also configured to include platinum (Pt) or palladium (Pd). In addition, the side-surface electrode contains gold (Au). The content ratio of gold in the side-surface electrode is preferably 3 to 20 weight %.

Abstract: There is disclosed a piezoelectric/electrostrictive element which can be used as a sensor, even if a piezoelectric/electrostrictive layer cracks. Provided is a piezoelectric/electrostrictive element comprising a substrate, a lower electrode layer secured onto the substrate, and a piezoelectric/electrostrictive layer secured onto the lower electrode layer, and the coverage of the lower electrode layer with respect to the substrate is 98% or less.

Abstract: There is disclosed a piezoelectric/electrostrictive element which can be used as a sensor, even if a piezoelectric/electrostrictive layer cracks. Provided is a piezoelectric/electrostrictive element 10 comprising a substrate 11, a lower electrode layer 12 secured onto the substrate 11, and a piezoelectric/electrostrictive layer 13 secured onto the lower electrode layer 12, and the coverage of the lower electrode layer 12 with respect to the substrate 11 is 98% or less.

Abstract: In a multilayered ceramic substrate having a ceramic substrate fireable in low temperatures and a metal member for input/output brazed to the ceramic substrate, an intermediate layer including a ceramic component is arranged between the ceramic substrate and the metal member in such a manner that thermal coefficients .alpha..sub.1, .alpha..sub.2 and .alpha..sub.3 between a room temperature and near a brazing temperature of the metal member, the ceramic component in the intermediate layer and the ceramic layer, respectively, maintains a relation of .alpha..sub.1 >.alpha..sub.2 >.alpha..sub.3. Moreover, the ceramic substrate fireable in low temperatures is constructed by first ceramic layer having a flexural strength more than 25 kg/mm.sup.2 and a second ceramic layer having a dielectric constant less than 7.