Tdk Corporation

Nec Corporation

Masayoshi Inoue

Toshiyuki Suzuki

Satoshi Sasaki

Masahito Furukawa

Hitoshi Oka

Masakazu Hirose

Takeo Tsukada

Satoshi Ozawa

Kazushi Tachimoto

Taeko Tsubokura

Yoshiki Ohta

Hideya Sakamoto

Junichi Yamazaki

Masaru Nanao

Nobuyuki Miki

Norimasa Sakamoto

Kazuo Miyabe

Keisuke Itakura

Kumiko Iezumi

Yoshiaki Ohta

Katsuya Inaba

Ryoichi Tanihata

Takahiro Kezuka

Rin Sato

Yuzo Komatsu

Yumiko Kozasa

Kenichiro Hirano

In a piezoelectric element, internal stress generated in an inactive portion at the time of sintering when a piezoelectric element is fabricated or stress applied from the outside to the inactive portion is absorbed by a recess of a lower surface of a first through hole conductor and a recess of an upper surface of a second through hole conductor. Accordingly, for example, deformation, rupture, or the like of the through hole conductor is prevented, and conduction failure or disconnection of an electrode layer or a through hole conductor is prevented. Further, in the inactive portion, since a protrusion of the piezoelectric layer enters the recess of the through hole conductor, a holding force of the piezoelectric layer with respect to the through hole conductor increases, and deformation of the through hole conductor is prevented or obstructed.

Piezoelectric element

Provided is a piezoelectric ceramic composition capable of being sintered at low temperatures and in a low-oxygen reductive atmosphere and capable of attaining a sufficient displacement even at high voltages of 1 kV/mm or more. The piezoelectric ceramic composition includes: a composite oxide, as a main constituent thereof, represented by the following composition formula; Cu and/or Ag, each as a first additive, Cu being included in a content &#x3b1;, in terms of CuO, falling within a range 0&#x3c;&#x3b1;&#x2266;0.5% by mass and Ag being included in a content &#x3b2;, in terms of AgO, falling within a range 0&#x3c;&#x3b2;&#x2266;0.4% by mass, in relation to the main constituent; wherein: composition formula: Pb[(ZnNb)TiZr]O, where 0.96&#x2266;a&#x2266;1.03, 0.005&#x2266;x&#x3c;0.05, 0.42&#x2266;y&#x2266;0.53, 0.45&#x2266;z&#x2266;0.56, and x+y+z=1.

Piezoelectric ceramic composition and laminated piezoelectric element

A piezoelectric substrate is constituted by a piezoelectric material of an effective Poisson's ratio being less than 1/3. The substrate has a pair of opposite faces and the opposite faces are provide with a pair of vibrating electrodes in correspondence. The opposite faces of the piezoelectric substrate are rectangular respectively. The sum of the lengths Lc of the one faces in the opposite faces and the length Wc of the other side of the same is limited within range 2.22 mm&lE;&lE;2.24 mm or 2.34 mm&lE;&lE;2.48 mm, said one faces being vertical each other. The areas Sc of the opposite faces are 1.22 mm &lE;Sc&lE;1.26 mm or 1.35 mm &lE;Sc&lE;1.538 mm . Accordingly, though using the piezoelectric material of the effective Poisson's ratio being less than 1/3, vibration in the thickness extensional fundamental waves can be steadily utilized.

Piezoelectric resonator and piezoelectric resonator part

Provided is a piezoelectric ceramic which achieves a high density, good temperature characteristics and a high Curie temperature, which can fully prevent (a) a decrease in Qmax (Qmax refers to a tan.theta.max when the maximum value of phase angles of third harmonic is a .theta.max), (b) a decrease in q (dynamic range of resonance frequency), (c) an increase in a fundamental wave and (d) the occurrence of a spurious mode in the vicinity of third harmonic, caused by downsizing, and which can materialize a small-sized high-performance piezoelectric element, the piezoelectric ceramic having a composition of the general formula,

Piezoelectric ceramics

A key telephone system has a plurality of telephone sets, each set having a hold button for temporarily holding a central office ('CO') line. A plurality of cell park lamps temporarily indicate which of the CO lines is being held. A plurality of call park buttons are individually associated with the call park lamps. An outgoing call button is used for seizing an idle one of the CO lines when an outgoing call is to be initiated. An answer button is used for seizing one of the CO lines over which an incoming call is being received. At least one external indicator indicates the various states (busy, idle, holding) of each of the CO lines. A central unit has a hold control circuit for indicating with the call park lamps when the CO line is being held responsive to an operation of either the hold button or a call park button. A CO line selecting circuit is provided for selecting and seizing an idle one of the CO lines, in response to an operation of the outgoing call button, and one of the CO lines over which an incoming call is being received in response to an operation of the answer button. A CO line indication control circuit controls the external indicator to indicate the states of the CO lines.

Key telephone system

Growing community of inventors

Tokyo, Japan

Masayoshi Inoue