Abstract: A piezoelectric filter is one not changing in the holding position of resonator in spite of impulse, small in the number of parts, easy to assemble from one direction, small, thin, and stable in characteristic. For example, as shown in FIG. 7, on electrode patterns on a package 10 forming wiring electrode patterns 11, holding protrusions 13 for holding resonators, and partition boards 14 for positioning resonators, a rectangular plate type piezoelectric resonators 12 are adhered with conductive adhesive. The rectangular plate type piezoelectric resonators 12 and the package 10 are adhered and reinforced from above with a vibration absorbing member 15, and wiring is formed from above the resonators by a wire bonding 16, thereby wiring resonators in a ladder form. Or, as shown in FIG.

Abstract: In a piezoelectric resonator having a piezoelectric bar formed in a substantial rectangular parallelopiped and electrodes formed on a pair of confronting surfaces of the piezoelectric bar for resonating in the length expander mode, the piezoelectric bar has at least a bevel portion extending the longitudinal direction. In a ladder filter having series and parallel piezoelectric resonators, the series piezoelectric resonator has the bevel portion to shift a frequency of a spurious response to that of the parallel piezoelectric resonator to suppress the spurious response. It is disclosed that a second piezoelectric resonator has a piezoelectric bar formed in a rectangular parallelopiped has a length L, a width W, and a thickness T wherein L>W>T; and electrodes formed on a pair of confronting surfaces defined by L and T. Another ladder filter includes the second piezoelectric resonator as the series resonator to decrease a capacitance between the electrodes to increase an amount of attenuation.

Abstract: A stress-sensitive sensor comprising a means for generating magnetic flux, a thin sheet of an amorphous magnetic alloy which is located in the magnetic flux and which is physically deformed in response to an external force to be measured, and a means for detecting the physical deformation as a variation of the magnetic flux which depends on the external force. The amorphous magnetic alloy consists essentially of Fe.sub.a Cr.sub.b Si.sub.c B.sub.d, in which a is a value of from 69 to 81.5 atomic percent, b is a value of from 2.5 to 6 atomic percent, c is a value of from 10 to 15 atomic percent, and d is a value from 6 to 10 atomic percent provided that a+b+c+d=100. The sensor is particularly suitable for oil pressure or torque detection.

Abstract: A fine adjustment apparatus for an optical system lens includes an annular laminated piezoelectric vibrator. The lens is attached to the inner peripheral portion of the piezoelectric vibrator. The piezoelectric vibrator is firmly supported at its outer peripheral portion by a proper member. The piezoelectric vibrator is deflected by the application of a voltage, whereby the lens is finely displaced in the optical axis direction thereof. The piezoelectric vibrator may be formed by laminating two annular piezoelectric elements with an annular metal plate sandwiched therebetween. Each of the piezoelectric elements has the axis of polarization extending in the thicknesswise direction thereof. The metal plate has a thickness which does not exceed at least 25% of the total thickness of the two piezoelectric elements.

Abstract: A stress or strain sensor including a magnetic circuit having at least a part constituted by an amorphous magnetic alloy. For detection of the inductance value of the sensor, a DC magnetic field is superposed on an AC magnetic field so that magnetic domains of the alloy tend to be aligned. The sensor output can be increased significantly over that of the conventional sensor in which only the AC magnetic field is employed, while hysteresis of the output is reduced. The temperature characteristic is also improved.

Abstract: An ultrasonic transducer having, in a throat part of a horn, a piezoelectric element and a diaphragm connected by a connection rod to the piezoelectric element. A disk having a plurality of apertures is disposed in front of the diaphragm, thereby improving the directivity and sensitivity without losing transient characteristic, making the transducer very suitable for ultrasonic distance measurement in air.

Abstract: An ultrasonic transmitter-receiver is characterized in that a diaphragm is disposed at the center of a laminated piezo-electric element and the periphery of the diaphragm is flexibly fixed in a housing through a buffer member of elastic rubber or the like in order to suppress mechanical oscillation.

Abstract: An ultrasonic transducer comprises a lamination structured piezo-electric element (1) to which center shaft (2) of a diaphragm (3) is connected, a housing (7) mounted integral with a horn (11), a buffer member (10) disposed between said housing (7) and said diaphragm (3) for holding said diaphragm (3) in vibratable manner; thereby a sharp rise up and fall down characteristics of ultrasonic wave and sharp directivity are attained.

Abstract: A tension sensor for sensing tension in the magnetic tape by measuring variations in an inductance value which arise as a result of applying stress which has been transformed from tension in the object to be measured to an amorphous magnetic alloy part of an inductance element. The magnetostrictive effect of the amorphous magnetic alloy which is both resilient and magnetostrictive is utilized in sensing the tension in the tape. The magnetic alloy is used for at least a part of a magnetic core of the inductance element.

Abstract: A pressure sensing unit for a pressure sensor using the magnetostriction effect of a ferrous amorphous magnetic alloy having elasticity which permits magnetostriction, and including an inductance element which has a magnetic core formed at least in part of the amorphous magnetic alloy and which is subjected to pressure so as to exert pressure on the alloy corresponding to the pressure to be measured, the resulting change in the value of the inductance being used to detect the applied pressure.

Abstract: An ultrasonic rangefinder providing a correct distance measurement and comprising a first transducer for transducing electric signals into ultrasonic waves and transmitting the ultrasonic waves, a second transducer for receiving the ultrasonic waves and transducing the ultrasonic waves into electric signals, a differentiation circuit, and a comparator for comparing a level of a differentiated output signal from the differentiation circuit with an output signal level of the second transducer and detecting a threshold time when the level of the differentiated output signal from the differentiation circuit becomes lower then the output signal level of the second transducer where a threshold signal level of the comparator is automatically varied with respect to a time lapse of the travelling ultrasonic waves coming back to the rangefinder after being reflected by an object, thus overcoming the conventional problems due to the spurious-like direct waves.

Abstract: A rotary magnetic head apparatus having a bending mode vibrator or vibrators mounted on a rotary cylinder, the vibrator comprising either ring shape piezoelectric vibrators bonded together with their polarization axes aligned in the direction of the thickness or the bonded piezoelectric vibrators bisected along a diameter of the ring, the bending vibrator mounting thereon a magnetic head or heads.

Abstract: This invention is directed to an apparatus capable of stably detecting humidity. More particularly, to stably detect the humidity in the atmosphere where temperature, relative humidity or wind flow vary, this humidity detecting apparatus converts the resistance variation, due to humidity, of a humidity-sensing resistor into voltage variation to draw out the voltage variation thereby to differentiate the voltage variation with a differential circuit and thereafter to compare the differentiation output with a set value. Therefore, the steam leakage from the high pressure, high temperature steam supply pipe or the relative humidity inside a microwave oven can be easily, automatically detected.