Murata Manufacturing Co., Ltd.

Murata Mfg. Co., Ltd.

Muneharu Yamashita

Jun Tabota

Toshihiro Mizuno

Jiro Inoue

Hiroshi Asano

Masayuki Ichimaru

Atsushi Mikado

Yasuharu Matsui

A method for manufacturing an electronic component includes preparing an element substrate having a function section for providing a function of an electronic component, and an external-connection electrode; bonding a low-sandblast-resistant case plate to the element substrate through a high-sandblast-resistant adhesive layer; forming, by sandblast processing, a hole in the case plate above the external-connection electrode so that the adhesive layer is exposed to the outside; removing, by etching, an adhesive layer portion that is exposed in the hole; forming an electrode film so as to be electrically connected to the exposed external-connection electrode; and forming, by mechanical machining, a projection having a leading end surface on which a terminal electrode resulting from the electrode film is defined.

Method for manufacturing electronic component, and electronic component

A mechanical quantity sensor includes a current-to-voltage converter/signal adder circuit that converts electric current signals flowing through two piezoelectric vibrators into voltage signals. The piezoelectric vibrators receive stresses generated by a mechanical quantity, such as acceleration, in opposite directions. A voltage amplifier/amplitude limiter circuit amplifies an added signal obtained from the two voltage signals and limits its amplitude. A phase-difference-to-voltage converter circuit detects a difference in the phases of the added signal and a feedback voltage signal applied to an acceleration detection element. A phase shifter circuit controls the phase of the feedback voltage signal so that the phase is a predetermined phase. A filter circuit minimizes frequency components higher than an oscillation frequency in an unwanted frequency band. By increasing the resistance of resistors so as to increase the damping ratio, temperature stability is increased. Accordingly, abnormal oscillation is prevented by the filter circuit, and fluctuation in the characteristics is minimized by the phase control circuit.

Mechanical quantity sensor

A piezoelectric-vibrator series circuit including two series-connected piezoelectric vibrators to which stresses induced by a dynamic quantity are applied in opposite directions is used, and a Colpitts oscillator circuit is defined by the piezoelectric-vibrator series circuit and an amplifier circuit/load impedance circuit. A phase-difference-to-voltage converter circuit is provided to convert a phase difference between an output voltage of the oscillator circuit and a voltage at a piezoelectric-vibrator series node of the piezoelectric-vibrator series circuit into a voltage signal.

Dynamic-quantity sensor

A dynamic-quantity sensor includes two piezoelectric vibrators which are arranged such that stresses generated by a dynamic quantity, such as acceleration, are applied in opposite phases to the piezoelectric vibrators. A current-voltage converting and signal adding circuit converts current signals flowing in the piezoelectric vibrators into voltage signals. A feedback signal processing circuit amplifies a combined signal of the two voltage signals and feeds back the combined signal to an acceleration sensing element, so that oscillation is performed. A self-diagnostic circuit including a series circuit including a switching circuit and a capacitor is provided between a reference potential (ground) and a node between one of the piezoelectric vibrators and a resistor in which a current of the one of the piezoelectric vibrators flows. Diagnosis is performed in accordance with whether or not a signal based on turning on and off of the switching circuit changes normally.

A mechanical-force sensor includes two piezoelectric vibrators which are arranged such that stresses in mutually opposite directions are applied thereto by a mechanical force such as an acceleration. A current-voltage converter and signal-summing circuit converts current signals that flow through the two piezoelectric vibrators into voltage signals. A voltage-amplifier and amplitude limiter circuit amplifies a sum signal of the two voltage signals, and provides a positive feedback of a voltage signal that is in phase with the current signals, thereby causing an oscillating operation. A phase difference-voltage converter circuit generates a voltage signal that is proportional to the phase difference between the voltage signals yielded by the conversion. An amplifier and filter circuit DC-amplifies the voltage signal and removes unwanted frequency components therefrom.

Mechanical force sensor

An amplification circuit for electric charge type sensor has a simple circuit configuration in which a common mode noise is adequately cancelled. In the acceleration sensor amplification circuit, the inversion input terminal of an operational amplifier is connected to one end of the acceleration sensor (G sensor). In addition, a feedback circuit including a feedback resistor and a feedback capacitor connected in parallel to each other is connected between the inversion input terminal and the output terminal of the operational amplifier. Furthermore, a cancellation circuit including a cancel resistor and a cancel capacitor connected in parallel to each other is connected between the non-inversion input terminal of the operational amplifier and a reference voltage.

Amplification circuit for electric charge type sensor

An acceleration sensor includes a bridge circuit including two capacitors and two piezoelectric vibrators on which reverse stresses are exerted by acceleration, and a voltage-dividing impedance circuit provided between a second junction point and a third junction point. The signal of a voltage-dividing point of the voltage-dividing impedance circuit is fed back to a first junction point, so that an oscillation circuit is provided. An oscillating-output phase difference between the second and third junction points is detected by a phase-difference-signal processing circuit and is output as an acceleration-detection signal.

Acceleration sensor

A charge-type sensor amplifying circuit includes an operational amplifier having an inverting input terminal thereof connected to one terminal of a charge-type sensor, a voltage divider having two voltage-dividing points which divide the output voltage from the operational amplifier, a feedback resistor connected between the inverting input terminal of the operational amplifier and one voltage-dividing point of the voltage divider which is on the output terminal side of the operational amplifier, and a feedback capacitor connected in parallel with the feedback resistor. In the charge-type sensor amplifying circuit, the other terminal of the charge-type sensor is connected to the other voltage-dividing point of the voltage divider which is not on the output terminal side of the operational amplifier.

Charge-type sensor amplifying circuit

A high-precision acceleration sensor capable of performing sensitivity adjustment by the sensor alone includes an acceleration sensing device disposed in an insulated case, in which external lead electrodes connected to the acceleration sensing device, a trimmable resistor, and external lead electrodes connected to both ends of the trimmable resistor, are formed on a surface of the insulating case. The trimmable resistor is a film-formed resistor made by printing. The sensitivity of the acceleration sensor can be adjusted by laser-trimming of the trimmable resistor.

An amplifier having an operational amplifier, and in which an output terminal of an acceleration sensor is connected to the non-inverting input terminal of the operational amplifier, a leakage resistor R,is connected between a non-inverting input terminal and the reference voltage, a first capacitor C,and a first resistor R,are connected in series with each other between the inverting input terminal and the reference voltage, first and second voltage dividing resistors are connected in series with each other between the output terminal of the operational amplifier and the reference voltage, and a second resistor R,and a second capacitor C,are connected in parallel with each other between the connection point of the voltage dividing resistors and the inverting input terminal, and the relationship C,&times;R,<C,&times;R,is satisfied.

Amplifier for piezoelectric acceleration sensor

An electric charge type sensor includes a detection element detecting a physical property to be detected and outputting a detection signal in the form of electric charge and an operational amplifier having an output terminal, an inversion input terminal and a non-inversion input terminal. The inversion input terminal is connected to the detection element while the non-inversion input terminal is connected to a reference potential. The electric charge type sensor further comprises a feedback capacitor, a voltage divider and a feedback resistor. The feedback capacitor is connected between the output terminal and the inversion input terminal. The voltage divider is connected to the output terminal for providing a partial voltage of an output voltage at the output terminal. A feedback resistor is connected between the voltage divider and the inversion input terminal.

Electric charge type sensor

An acceleration sensor 1 comprises a circuit board 3 on which an acceleration detecting element 2 is carried. A plurality of connecting terminals 4 arranged along the periphery of the circuit board 3 are projected outward after penetrating through a metal base plate 5. The metal base plate 5 is fixed to the connecting terminals 4 spaced apart from the circuit board 3 by a predetermined distance in a state being insulated from the connecting terminals 4. The peripheral edge of the metal base plate 5 is connected to a case 7 covering the entire acceleration sensor 1. Circuit elements constituting a signal processing circuit for processing a detection signal of the acceleration detecting element 2 are arranged on the upper surface and the lower surface of the circuit board 3.

Acceleration sensor with a circuit board separated from a base plate by

A surface potential sensor which is less affected by noise superposed on a reference source voltage than prior sensors, and hence can improve measurement accuracy with ease, and which also has higher stability against extraneous noise. The sensor includes an initial-stage input circuit comprising an FET, and a succeeding-stage amplifier circuit mainly comprising an operational amplifier for amplifying a difference between an AC component from the initial-stage input circuit and a reference source voltage. A resistor is connected between a drain of the FET constituting the initial-stage input circuit and a source voltage line to take out a signal from the FET drain. The source voltage supplied to the FET is the reference source voltage.

Surface potential sensor and processing circuit having improved noise

An ultrasonic rangefinder capable of effectively removing high-level, directly transmitted wave components. The rangefinder can be used even at low temperatures. The rangefinder comprises an input signal-processing circuit, an output signal-processing circuit, and a gain control circuit inserted between the input and output signal-processing circuits. The output signal-processing circuit includes a reception amplification circuit and a detection circuit, the reception amplification circuit having an amplifier. The gain control circuit lowers the gain of the reception amplification circuit to raise the undetected and detected input voltage levels applied to the detection circuit. The gain control circuit comprises three control devices. The first control device is driven into conduction when its input pulse signal varies from a low level to a high level. The second control device reduces the feedback resistance of the amplifier of the reception amplification circuit in response to conduction of the first control device. In response to conduction of the first control device, the third control device controls the time for which the second control device operates.

Growing community of inventors

Toyama-ken, Japan

Muneharu Yamashita