Tdk Corporation

Komatsu Corporation

Kelk Ltd.

Kazuo Miyabe

Hitoshi Oka

Masakazu Hirose

Tadashi Takenaka

Daisuke Goto

Kenji Horino

Kazushi Tachimoto

Taeko Tsubokura

Tomonori Murata

Hirokuni Hachiuma

Masayoshi Inoue

You Sangawa

Ryoji Kasuya

Mahoko Takada

An optical sensor is provided, in which members forming an optical path can be reliably supported without blocking the optical path extending from a light source to a light receiver. An optical sensor includes a light source configured to emit light, and a light receiver configured to receive the light emitted from the light source. An optical path extending from the light source to the light receiver extends through an oil infiltrating space into which oil infiltrates. The optical sensor further includes: a substrate on which the light source is mounted; a substrate on which the light receiver is mounted; a fixing member including an accommodation space in which the substrates are accommodated; and a sealing resin contained in the accommodation space and sealing the substrate.

Optical sensor

The object of the present invention is to realize the piezoelectric ceramics which, even when used as high frequency elements utilizing third harmonics wave of thickness longitudinal vibration, are small in temperature coefficient of resonant frequency and high in mechanical Q value and easy to correspond to the trend toward miniaturization and low voltage driving. When the piezoelectric ceramics with lead titanate as its main component are manufactured in order to achieve this object, it was decided that the piezoelectric ceramics be manufactured by the manufacturing method, wherein a heat treatment is performed between a firing process and a polarization process in the atmosphere of oxygen partial pressure less than the oxygen partial pressure of the atmospheric pressure at temperatures more than 500.degree. C. and not more than the firing temperatures.

Method of preparation of piezoelectric ceramics

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 lead-oxide-free piezoelectric ceramic composition having an electromechanical coupling coefficient greater than a predetermined value and having a Curie point of at least 500.degree. C., whose main component is a two-component-based solid solution of the formula of (1-x)Bi.sub.a Ti.sub.b Nb.sub.c O.sub.9 -xNa.sub.p Bi.sub.q Nb.sub.r O.sub.9, and which has a bismuth layer structure in the range of 0&lt;x&lt;1,

Piezoelectric ceramic composition

One object of the present invention is to provide a lead-free piezoelectric material excellent in piezoelectric characteristics and superior from the viewpoints of prevention of environmental pollution, protection of environments and ecology. To achieve the object, a piezoelectric ceramic composition is constructed from a piezoelectric ceramic composition within a region in case of being represented by the formula:

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Tokyo, Japan

Kazuo Miyabe