Yamaha Corporation

Yukitoshi Suzuki

Tamito Suzuki

Masayoshi Omura

Kazushi Sakurauchi

Kenichi Shirasaka

Toshihisa Suzuki

Seiji Hirade

Nariyasu Yaguchi

Tatsuya Hiraku

Masuhiro Okada

Masao Imanishi

Akira Kaneko

Yuusaku Ebihara

Mineko Kosugi

A pressure sensor according to an aspect of the present invention comprises a plurality of piezoelectric elements that are sheet-like and laminated, wherein: the plurality of piezoelectric elements are divided into a plurality of element groups; and the plurality of element groups are connected in parallel and in each element group the piezoelectric elements are connected in series, or the plurality of element groups are connected in series and in each element group the piezoelectric elements are connected in parallel.

Pressure sensor having a plurality of sheet-like and laminated piezoelectric elements

A condenser microphone includes a substrate having a cavity, first and second spacers defining an opening, a diaphragm having a rectangular shape positioned inside of the opening, and a plate having a rectangular shape positioned just above the diaphragm. Plate joint portions integrally interconnected with two sides of the plate are directly attached onto the second spacer. Supports, which are attached onto the second spacer across the opening and project inwardly of the opening, are connected to the prescribed portions of the diaphragm via third spacers relatively to the other two sides of the plate. The center portion of the diaphragm can be designed in a multilayered structure, and the peripheral portion can be bent outwardly. In addition, both ends of the diaphragm are fixed in position, while free ends of the diaphragm vibrate due to sound waves.

Condenser microphone

A plurality of structures of condenser microphones is fabricated in a single condenser microphone array chip. The condenser microphone array chip includes a substrate having a plurality of openings serving as air cavities, a first insulating layer formed in the outer periphery of the openings, a first electrode layer stretched over each of the openings, a second insulating layer formed above the first electrode layer in the outer periphery of the openings, a second electrode layer formed above the second insulating layer relative to the first electrode layer via an air gap therebetween. The structures are connected via a plurality of bridges and separated via a plurality of channels therebetween. The channels circumvent the bridges so that at least the second insulating layer is partially removed from the channels. The bridges are formed using the second electrode layer serving as wiring for electrically connecting the structures of condenser microphones.

Condenser microphone array chip

The present invention provides a condenser microphone, in which, with a simple manufacturing process, vibration characteristics of a diaphragm are improved, and a parasitic capacitance occurring between the diaphragm and a back plate is reduced, thus improving sensitivity. Specifically, the diaphragm having a gear-like shape including a center portion and a plurality of arms and the back plate having a gear-like shape including a center portion and a plurality of arms are positioned opposite to each other above a substrate, wherein the arms of the diaphragm and the arms of the back plate are not positioned opposite to each other. Alternatively, it is possible to independently support the diaphragm and the back plate above the substrate. Furthermore, it is possible to support the back plate above the substrate by means of a plurality of supports inserted into a plurality of holes formed in the center portion of the diaphragm.

A capacitor microphone is constituted by a plate having a fixed electrode, a diaphragm including a center portion and at least one near-end portion that is fixed to the outer periphery, in which the center portion having a vibrating electrode, which is positioned relative to the fixed electrode and which vibrates in response to sound waves, is increased in rigidity in comparison with the near-end portion; and a spacer that is fixed to the plate and the near-end portion of the diaphragm and that has an air gap formed between the plate and the diaphragm. Alternatively, a diaphragm electrode is horizontally supported by extension arms extended from a circular plate thereof and is vertically held in a hanging state being apart from a fixed electrode with a controlled distance therebetween.

Capacitor microphone

An MEMS transducer is constituted of a diaphragm, a plate, a support structure for supporting the diaphragm and the plate with a gap layer surrounded by an interior wall, an electrode film (e.g. a pad conductive film) for covering a contact hole formed in the support structure, and a protective film (e.g. a pad protective film) which is formed on the support structure externally of the interior wall so as to cover the side surface of the electrode film having low chemical stability. The protective film is formed in the limited area including a part of the surface of the electrode film except for its center portion and the surrounding area of the electrode film. This allows the protective film to use materials having high membrane stress such as silicon nitride or silicon nitride oxide.

MEMS transducer

A semiconductor device is equipped with a semiconductor sensor chip for detecting pressure variations that is arranged inside of a hollow cavity of a housing, wherein an opening is formed in a prescribed region of the housing, which is not positioned opposite to the semiconductor sensor chip, so as to allow the hollow cavity to communicate with an external space. The opening is formed using at least one through-hole having a thin slit-like shape. Alternatively, the opening is formed using plural through-holes each having a desired shape such as a thin slit-like shape, a circular shape, and a sectorial shape. Thus, it is possible to reduce negative influences due to environmental factors such as dust and sunlight with respect to the semiconductor sensor chip.

Semiconductor device

A surface acoustic wave device (e.g., filter or convolver) is designed to increase an electromechanical coupling factor K and is basically configured by a substrate, a buffer layer, a piezoelectric layer and an electrode layer. Herein, the substrate is made of a bulk material (e.g., SrTiO ), which allows growth of a perovskite compound crystal being expressed by a general chemical formula of SrZO (where Z denotes an element such as Zr and Sn whose valence is 4). The buffer layer is formed on the substrate and is made of the perovskite compound crystal (e.g., SrZrO , SrSnO ), which has good lattice matching with KNbO . The piezoelectric layer is made of a KNbO single crystal and is formed on the buffer layer with a thickness of 500 nm or so. The electrode layer is formed on or below the piezoelectric layer. An interdigital transducer consisting of input and output electrodes is formed by patterning using photolithography technique being effected on the electrode layer, which is made of a metal material (e.g., Al). In addition, it is possible to form a temperature stabilization layer between the piezoelectric layer and electrode layer. The temperature stabilization layer is made of a material (SiO ) having a temperature coefficient reverse to a temperature coefficient of the piezoelectric layer so as to ease distortion being caused to occur due to differences in thermal expansion between the piezoelectric layer and electrode layer. Incidentally, the temperature stabilization layer has a prescribed thickness, which is approximately 1000 nm.

Growing community of inventors

Hamamatsu, Japan

Yukitoshi Suzuki