National Institute of Advanced Industrial Science and Technology

Denso Corporation

Ube Industries, Inc.

Agency of Industrial Science and Technology

Naohiro Ueno

Morito Akiyama

Hiroshi Tateyama

Kiichi Ikeda

Toshihiro Kamohara

Hiroyuki Nakamura

Yukihiro Takeuchi

Kazuhiko Kano

Tetsuo Yamada

Akihiko Teshigahara

Kazuhiro Nonaka

Keigo Nagao

Nobuaki Kawahara

Chisen Hashimoto

Yoshihiro Umeuchi

Keiichiro Jinushi

Osamu Fukuda

Noriyuki Kuwano

Masayoshi Tsubai

Yoshitaka Sunagawa

Pressure distribution on a surface of an ultrasonic probe can be measured directly. Piezoelectric sensors, in which a piezoelectric thin film is formed on a film-like substrate, are arranged in the form of an array on the surface of an ultrasonic probe, and a sensor output signal processing unit outputs pressure measured for each piezoelectric sensor S, Sto Sbased on output signals from each of the piezoelectric sensors to an image processing unit. The image processing unit generates a histogram of the measured pressures for piezoelectric sensors S, Sto S, and displays the histogram, while plotting the piezoelectric sensors on the X axis and the measured pressures on the Y axis, along with the resulting ultrasound tomographic image, on a monitor.

Ultrasound diagnostic apparatus

A piezoelectric thin film of the present invention includes an aluminum nitride thin film that contains scandium. A content ratio of scandium in the aluminum nitride thin film is 0.5 atom % to 50 atom % on the assumption that a total amount of the number of scandium atoms and the number of aluminum atoms is 100 atom %. According to this arrangement, the piezoelectric thin film of the present invention can improve a piezoelectric response while keeping characteristics of elastic wave propagation speed, Q value, and frequency-temperature coefficient that the aluminum nitride thin film has.

Piezoelectric thin film, piezoelectric material, and fabrication method of piezoelectric thin film and piezoelectric material, and piezoelectric resonator, actuator element, and physical sensor using piezoelectric thin film

A thin film made of a wurtzite structure compound is manufactured by a reactive sputtering using a metal material as a target, and a nitrogen gas or oxygen gas as a reactive gas. By optimizing film-forming conditions when manufacturing the film, it is possible to obtain a wurtzite thin film whose polarization directions of crystal grains are aligned in a uniform direction. There is provided a laminate including a first wurtzite crystalline layer made of a wurtzite crystalline structure compound is formed in advance between a substrate and a functional material layer that is a ground. Thus it is possible to improve the crystallinity and crystalline orientation of a second wurtzite crystalline layer on the functional material layer.

Wurtzite thin film, laminate containing wurtzite crystalline layer and their manufacturing methods

A lower electrode is formed on a silica glass substrate or a stainless substrate. Through a sputtering process, a thin film of aluminum nitride and/or zinc oxide is formed on the lower substrate so that the degree of dipole-orientation becomes 55% or more, and thereby a piezoelectric thin film is formed. And an upper electrode is formed on the piezoelectric thin film. A piezoelectric device has a piezoelectric layer made of aluminum nitride and/or zinc oxide. Aluminum nitride and zinc oxide with a crystal structure have inborn piezoelectric characteristics because their crystal structures are not symmetrical, they do not have Curie temperature unlike ferroelectrics, and in aluminum nitride and zinc oxide, magnetic transition does not occur even at high temperature, so that they never lose piezoelectric characteristics until crystal melts or sublimates.

Piezoelectric element and method for manufacturing

The present invention has an objective to provide a high performance piezoelectric element in which is formed an aluminum nitride thin film free from hillocks, cracks, and peeling which exhibits superhigh c-axis orientation, by forming a bottom electrode from a W layer with no intervening adhesive layer on a glass or other cheap substrate. The piezoelectric element of the present invention is a piezoelectric element using a superhigh-oriented aluminum nitride thin film characterized in that the piezoelectric element is free from hillocks, cracks, and peeling and includes a stack structure in which a bottom electrode, a piezoelectric body thin film, and a top electrode are sequentially formed on a substrate; the bottom electrode is made of an oriented W layer of which a (111) plane of W is parallel to a surface of the substrate; and the piezoelectric body thin film is formed of a c-axis-oriented aluminum nitride thin film having a rocking curve full width half maximum (RCFWHM) not exceeding 2.5&#xb0;.

Piezoelectric device comprising ultrahighly-oriented aluminum nitride thin film and its manufacturing method

A piezoelectric sensor arranged so as to includes: a transparent piezoelectric element having a piezoelectric property; and a pair of transparent conductor film layers opposed to each other with the piezoelectric element therebetween, the transparent piezoelectric element and the transparent conductor film layers are formed between a pair of transparent substrates, opposed to each other, which serve as pressure transmission means. Consequently, the transparent piezoelectric sensor has an excellent durability. A piezoelectric sensor comprises a piezoelectric element with a piezoelectric property which is made of a piezoelectric material having no Curie point and has a dipole orientation degree of not less than 75%. Consequently, the piezoelectric sensor having an excellent durability and a simple structure is provided at low cost.

Piezoelectric sensor and input device including same

A thin film bulk acoustic resonator comprises a substrate () of a silicon single crystal, a base film () formed on the substrate () and composed of a dielectric film mainly containing silicon oxide, and a piezoelectric stacked structure () formed on the base film (). A vibratory section () composed of a part of the base film () and a part of the piezoelectric stacked structure (). The piezoelectric stacked structure () includes a lower electrode (), a piezoelectric film (), and an upper electrode () formed in this order from below. The substrate () had a via hole () in the region corresponding to the vibratory section (). The via hole forms a space for allowing vibration of the vibratory section (). The piezoelectric film () is an aluminum nitride thin film containing 0.2 to 3.0 atom % of alkaline earth metal and/or a rare earth metal. Thus, the thin film bulk acoustic resonator has a high performance such as a large electromechanical coupling coefficient, an excellent acoustic quality factor (Q) and an excellent frequency-temperature characteristic.

Film bulk acoustic resonator

A thin pressure sensor includes: a pair of external electrodes, which are respectively made of conductive thin films that are respectively provided with piezoelectric layers on inner sides; and a single internal electrode, made of a conductive thin film, which is sealed between the pair of external electrodes, one of the pair of external electrodes having a conducting window that conducts to said internal electrode. The thin pressure sensor has a simple and thin structure with sufficient durability and mechanical strength.

Thin pressure sensor and biological information measuring device using same, and biological information measuring method

Disclosed is a high-sensitivity flexible ceramic sensor for detecting mechanical shocks and vibrations, which comprises a metal foil of a specified thickness as a substrate, a single-crystalline thin film of a piezoelectric ceramic material such as aluminum nitride and zinc oxide having a specified thickness formed on the substrate, a metallic electrode formed on the thin ceramic film and an external circuit connecting the metal foil and the electrode with insertion of an electric meter for measuring the piezoelectric voltage changes induced in the ceramic thin film.

High-sensitivity flexible ceramic sensor

The invention discloses a method for fine control of the flow rate of a liquid by a microvalve device without using any mechanical structures. The method comprises, while passing the liquid through a flow channel penetrating a substrate of a heat-insulating material, the temperature of the liquid in the flow channel is decreased below the freezing point of the liquid by a temperature-controlling means such as a Peltier element facing the flow channel to close the flow channel by the solidified liquid and the temperature of the solidified liquid is increased above the melting point thereof to cause thawing of the solid resulting in re-opening of the flow channel.

Growing community of inventors

Tosu, Japan

Naohiro Ueno