Denso Corporation

Nippondenso Co., Ltd.

Nozomu Okumura

Makoto Takagi

Toshihiro Miyake

Takashi Kurahashi

Yasuhiro Suzuki

Koji Kondo

Akira Fujii

Takeshi Senoo

Isao Mizuno

Yoshitsugu Sakamoto

Fusao Hirose

Toru Imura

Atsushi Iwase

Hideshi Mori

Koii Kondo

To provide a stacked piezoelectric device which is inexpensive and excellent in bonding strength between a piezoelectric layer and an internal electrode layer, the piezoelectric device comprises piezoelectric layers and internal electrode layers containing not less than 50 percent by weight of Cu stacked alternately. Between the internal electrode layer and the piezoelectric layer, there is a diffusion region formed by mutual diffusion of components of the internal electrode layer and the piezoelectric layer to the other layer and comprising at least one component of the piezoelectric material and Cu. The diffusion region occupies not less than 90 percent of area of interface between the internal electrode layer and the piezoelectric layer, and a thickness of the diffusion region is not more than 10 percent of a thickness of the internal electrode layer. A piezoelectric material constituting the piezoelectric layer preferably comprises PZT which is a Pb(Zr,Ti)O&#x2014; based oxide having a perovskite structure, and Pb, Cu, and O elements coexist in the diffusion region.

Stacked piezoelectric device and method of fabricating same

A stacked piezoelectric device, which is inexpensive and excellent in electric transmission efficiency and little deterioration of strength of an internal electrode layer, is provided by having an internal electrode layer containing not less than 50 percent by weight of Cu element, and not more than 5 percent of a pore occurrence expressed by (B/A)&#xd7;100 (%) wherein A is an area of an interface between the internal electrode layer and the piezoelectric layer and B is a sum of areas of pores which appear in the interface and have a diameter of not less than 0.1 micrometers. Preferably, a surface roughness Ra of the interface of the piezoelectric layer contacting the internal electrode layer is not more than 0.5 C (&#x3bc;m) wherein C is a thickness of the internal electrode layer in micrometers. The piezoelectric material constituting the piezoelectric layer preferably comprises PZT which is a Pb(Zr,Ti)O-based oxide having a perovskite structure.

Stacked piezoelectric device

A connecting material, which secures reliable joints without using flux, is disclosed. Soldering is performed using an auxiliary connecting material capable of physically destroying and dispersing an oxide film, which is naturally grown on the surface of a main connecting material such as solder or brazing between two terminals, to realize a reliable solder wetting (a state of the main connecting material being fused and mixed). For an auxiliary connecting material, hydrocarbon such as n-tetradecane (C H ), for example, can be used. N-tetradecane boils between connection surfaces and cubically expands; energy generated therefrom physically disperses the oxide film and causes a fresh surface to be exposed; solders on both terminals are mixed; and an electrical and mechanical joint is securely achieved. The residue of the auxiliary connecting material is an insulating material, and therefore does not need cleaning. An excellent electrical joint which is moisture-resistant as well as highly reliable is attained.

Soldered product

A soldered product having secure reliable joints, without the use of flux, is disclosed. The soldered product includes a first member having a connected portion and a second member, also having a connected portion, facing the first member. The connected portions of the first and second members are electrically connected by a connecting material. A layer of hydrocarbon, including alkane, alkene or alkyne, is disposed around the periphery of the connecting material.

An electrode comprises an active substance therefor which is made of a shaped body of a carbon porous body and a low crystallinity or amorphous carbon layer formed on at least a part of surfaces of the carbon porous body. The carbon porous body further comprises crystalline carbon particles which are dispersed and held in the carbon porous body. A method for making the electrode and a nonaqueous electrolyte secondary cell comprising the electrode as a negative electrode are also described.

Carbon electrode for secondary cells, a method for making the same, and

A soldering method, which secures reliable joints without using flux, is disclosed. Soldering is performed using an auxiliary connecting material capable of physically destroying and dispersing an oxide film, which is naturally grown on the surface of a main connecting material such as solder or brazing between two terminals, to realize a reliable solder wetting (a state of the main connecting material being fused and mixed). For an auxiliary connecting material, hydrocarbon such as n-tetradecane (C.sub.14 H.sub.30), for example, can be used. N-tetradecane boils between connection surfaces and cubically expands; energy generated therefrom physically disperses the oxide film and causes a fresh surface to be exposed; solders on both terminals are mixed; and an electrical and mechanical joint is securely achieved. The residue of the auxiliary connecting material is an insulating material, and therefore does not need cleaning. An excellent electrical joint which is moisture-resistant as well as highly reliable is attained.

Soldering method

A strain sensor for detecting strain in automobiles, robots, and the like includes a magnetostrictive layer. The magnetostrictive layer is formed by irradiating an alloy layer with a high energy density beam (such as a laser) to form a magnetostrictive layer having an amorphous structure. The resulting magnetostrictive layer has a magnetic inductance in the direction of irradiation that is much higher than in a perpendicular direction thereof. Using such a sensor, it is possible to selectively detect components of stresses and strains in a given direction.

Method of formation of magnetostrictive layer and strain sensor using

In a distributor having a pair of electrodes, which comprises a rotor electrode and a side electrode, at least one electro-conductive metal member is disposed between the pair of electrodes to extend from one to the other, whereby generation of radio noise is suppressed.

Growing community of inventors

Nagoya, Japan

Nozomu Okumura