Matsushita Electric Industrial Co., Ltd.

Tetsuro Otsuchi

Osamu Kawasaki

Katsu Takeda

Katsumi Imada

Katsunori Moritoki

Masato Sugimoto

Yoshihiro Tomita

Hiroshi Kagata

Junichi Kato

Tetsuyoshi Ogura

Kouji Kawakita

Masanori Sumihara

Takahiro Nishikura

Takashi Nojima

Shigeo Suzuki

Hidenobu Shintaku

Fumihiko Taniguchi

Takafumi Koike

An acceleration sensor housed in a confined space can detect rotational acceleration with great accuracy. The acceleration sensor has first and second piezoelectric elements with electrodes for outputting a charge produced by strain deformation. Each of the first and second piezoelectric elements has at least one piezoelectric body and a support block for supporting the piezoelectric body. The electrodes are provided on opposite sides of the piezoelectric body. One surface of the first piezoelectric element and one surface of the second piezoelectric element are substantially parallel to each other.

Acceleration sensor, an acceleration detection apparatus, and a positioning device

A piezoelectric element includes a piezoelectric substrate formed of a piezoelectric material and a pair of electrodes formed on a first principal plane and a second principal plane of the piezoelectric substrate, wherein thickness shear vibration occurs, and the vibration direction of the thickness shear vibration is nonparallel to the side walls of the piezoelectric substrate.

Piezoelectric element having thickness shear vibration and mobile communication device using the same

A method for producing an acceleration sensor comprising an electromechanical transducer having a piezoelectric element includes providing at least two piezoelectric substrates where each has two opposing main surfaces. The piezoelectric element is formed by directly connecting one of the main surfaces of one of the at least two piezoelectric substrates with an opposing one of the main surfaces of another one of the at least two piezoelectric substrates. Supporters are provided to support the electromechanical transducer and are directly connected to the at least two piezoelectric substrates composing the piezoelectric element. Electrodes that extend continuously from the unconnected main surfaces of the at least two piezoelectric substrates composing the piezoelectric element to surfaces of the supporters are then formed.

Method for producing an acceleration sensor

A head actuator mechanism characterized has a head that records and reproduces data; a suspension that holds the head; a support arm; a drive means for moving the support arm; a coupling section for coupling the support arm and the suspension together in such a way that the head can move relatively to the support arm; and at least one piezoelectric element for coupling the support arm and the suspension together to move the head relatively to the support arm for fine tuning, the piezoelectric element being fixed to the support arm and suspension at both ends.

Head actuator driven by piezoelectric element

An acceleration sensor has a piezoelectric element which includes a piezoelectric member layer in which a plurality of piezoelectric members are stacked and electrodes which are disposed in major opposed surfaces of the piezoelectric member layer; and a support member for supporting the piezoelectric element, wherein some piezoelectric members of the piezoelectric member layer are polarized. The electrodes are disposed in both surfaces of the polarized piezoelectric members. Capacitors which are formed by the polarized piezoelectric members and the electrodes in both surfaces of the polarized piezoelectric members are connected parallel to each other.

Acceleration sensor

An acceleration sensor includes: a piezoelectric vibrator including a piezoelectric element having a first principal surface and a second principal surface opposed each other, a first and a second electrode formed on the first and the second principal surface, and conductive protrusions made of a metal material or a ceramic material and formed by a thermal spraying process; and a holding body for holding the piezoelectric vibrator via the conductive protrusions.

Acceleration sensor and method for producing the same

A small accelaration sensor which is highly sensitive over a large frequency region and which varies little in characteristics such as sensitivity. A piezoelectric element is formed by connecting two main faces of retangular LiNbO.sub.3 piezoelectric substrates, in which the polarization axes are directed oppositely. Supporters comprising LiNbO.sub.3 directly connected to one end of the piezoelectric element. Eletrodes of chromium-gold being 0.2 .mu.m are thick are successively connected to the two main faces of the piozoelectric element and to the supporters, thus to produce a cantilever structure bimorph electromechanical transducer.

Acceleration sensor and shock detecting device using the same

An acceleration sensor has a piezoelectric element which includes a piezoelectric member layer in which a plurality of piezoelectric members are stacked and electrodes which are disposed in major opposed surfaces of the piezoelectric member layer; and a support member for supporting the piezoelectric element, wherein some piezoelectric members of the piezoelectric member layer are polarized, the electrodes are disposed in the both surfaces of the polarized piezoelectric members, capacitors which are formed by the polarized piezoelectric members and the electrodes in the both surfaces of the polarized piezoelectric members are connected parallel to each other.

Rectangular piezoelectric substrates each of which has main surfaces opposed to each other, measures 50 .mu.m thick by 1 mm wide by 8 mm long, and is made of lithium niobate (LiNbO.sub.3), are directly bonded on the main surfaces so that their axes of polarization are set in directions reverse to each other, thereby composing a piezoelectric element. Electrodes which are 0.2 .mu.m thick and made of chromium-nickel are formed on the two main surfaces of the piezoelectric element opposed to each other, thereby resulting in a precision displacement control actuator of a bimorph type mechanical-electrical converter element. This configuration makes it possible to provide a compact precision displacement control actuator which has a large displacement and extremely small variations of characteristics such as displacement and resonance frequency.

Displacement control actuator

The present invention relates to a method for driving an ultrasonic motor of the type which includes a vibrator for causing a flexural vibration wave in response to a pair of AC driving voltage signals, and a rotor in contact with the vibrator and moved by the flexural vibration wave. The rotational speed of the ultrasonic motor is controlled by using a feedback signal and a data table, the feedback signal indicating the current rotational speed of the ultrasonic motor, and the data table storing values of the feedback signal as a standard function of the rotational 21 speed. The method includes the step of sampling the feedback signal and detecting the rotational speed in a plurality of rotation states of the ultrasonic motor. The method obtains an approximate function representing the relationship between the sampled feedback signal and the detected rotational speed of the ultrasonic motor, and calculates correction coefficients for adjusting the approximate function to the standard function. The method then controls the rotational speed of the ultrasonic motor by using the feedback signal. In the controlling step, the method corrects the feedback signal obtained from the ultrasonic motor by using the correction coefficient, whereby a value of the approximate function is transformed into a corresponding value of the standard function.

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Osaka, Japan

Tetsuro Otsuchi