Ngk Spark Plug Company, Limited

Takashi Kasashima

Yasuyuki Okimura

Kazushige Ohbayashi

Hisashi Kozuka

Masato Yamazaki

Hideto Yamada

Takayuki Matsuoka

Toshiaki Kurahashi

Kazuaki Kitamura

Toshitaka Honda

Hirokazu Kurono

Haruki Yoshida

Takeshi Mitsuoka

Manabu Sato

Kuniharu Tanaka

Jun Otsuka

Hironori Uegaki

Katsuya Takaoka

Katsuya Yamagiwa

Noriyasu Sugimoto

Kazuhiro Kurosawa

Kazuhisa Itakura

Takashi Oba

Masahiko Matsumiya

A lead-free piezoelectric ceramic composition including an alkali niobate/tantalate perovskite oxide main phase having piezoelectric properties and a different metal oxide. The mole ratio (Na/K) between Na (sodium) and K (potassium) in the main phase is 0.40&#x3c;(Na/K)&#x3c;3.0. The main phase has a crystal structure in which (i) first spots corresponding to a primitive lattice period and (ii) second spots corresponding to the lattice period two times the primitive lattice period and being weaker than the first spots appear in an electron beam diffraction image entering from the &#x3c;100&#x3e; direction with the main phase represented as a pseudo-cubic crystal system. Also, the area ratio of a crystal phase reflecting the second spots in the main phase is 33% or less, and the maximum grain size of crystals reflecting the second spots in the main phase is 25 nm or less.

Lead-free piezoelectric ceramic composition, piezoelectric element using the same, and method of manufacturing lead-free piezoelectric ceramic composition

A lead-free piezoelectric ceramic composition including an alkali niobate/tantalate perovskite oxide main phase having piezoelectric properties and a different metal oxide subphase. The mole ratio (Na/K) between Na (sodium) and K (potassium) in the main phase assumes a value in a range represented by 0.40&#x3c;(Na/K)&#x3c;3.0. The main phase has a crystal structure in which (i) first spots corresponding to a primitive lattice period and (ii) second spots corresponding to the lattice period two times the primitive lattice period and being weaker than the first spots appear in an electron beam diffraction image entering from the &#x3c;100&#x3e; direction with the main phase represented as a pseudo-cubic crystal system.

A lead-free piezoelectric ceramic composition includes a first crystal phase made of an alkali niobate/tantalate type perovskite oxide having piezoelectric properties, and a second crystal phase made of an M-Ti&#x2014;O spinel compound (where the element M is a monovalent to quadrivalent element).

Unleaded piezoelectric ceramic composition, piezoelectric element using same, device, and method for manufacturing unleaded piezoelectric ceramic composition

A connection portion connecting a center electrode and a terminal metal fixture together in a through hole of the insulator includes a resistor and a magnetic substance structure including a magnetic substance and a conductor and being disposed on a leading end side or a rear end side of the resistor while being positioned away from the resistor. The connection portion further includes a first conductive sealing portion, a second conductive sealing portion and a third conductive sealing portion. The first conductive sealing portion is disposed on a leading end side of a first member and is in contact therewith. The second conductive sealing portion is disposed between the first member and a second member and is in contact with the first and second members. The third conductive sealing portion is disposed on a rear end side of the second member and is in contact therewith.

Spark plug

Disclosed are a dielectric resonator having simple configuration applicable to a multiple mode with no electrical signal transmission loss, and a method of controlling a resonance state (coupling mode) in the dielectric resonator. The dielectric resonator includes a cylindrical or polygonal external conductor, and a dielectric resonant element arranged at the substantially center of the external conductor. A notched portion is formed at a part of the dielectric resonant element so as to control the resonance state of the dielectric resonator.

Dielectric resonator having a dielectric resonant element with two oppositely located notches for EH mode coupling

A dielectric material containing at least one of Ca and Sr, Ti, Al, at least one of Nb and Ta, and O, wherein these elements fulfill the following four requirements when represented by a compositional formula, aMO-bTiO-(&#xbd;)cAlO-(&#xbd;)dMOwherein Mrepresents the at least one of Ca and Sr; Mrepresents the at least one of Nb and Ta; and a, b, c and d represent each a molar ratio, provided that a+b+c+d=1: 0.436&#x3c;a&#x2266;0.500; 0.124&#x3c;b&#x2266;0.325; 0.054&#x3c;c&#x2266;0.150; and 0.170&#x3c;d&#x3c;0.346.

Dielectric material

A dielectric composition is based on a BaO&mdash;MgO&mdash;Nb O system material (BMN system material) having a dielectric constant, &egr;, of about 30, a large Q-value (no-load quality coefficient) and a comparatively small absolute value of the temperature coefficient (&tgr; ) of its resonance frequency but containing no expensive Ta. The dielectric material has a composite perovskite crystal structure as the main crystal phase, wherein a predetermined amount of KNbO is added to a BMN system material. The high frequency characteristics can be further improved by partially replacing Nb with Sb and partially replacing the B site of the perovskite crystal structure with Sn.

Dielectric composition for high frequency resonators

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Ichinomiya, Japan

Takashi Kasashima