Murata Manufacturing Co., Ltd.

Masao Nishimura

Toshinari Tabata

Yoshinao Nishioka

Mitsuru Kitagawa

Masato Ikuta

A piezoelectric ceramic device is heated so that the temperature is increased to a temperature in the vicinity of the maximum temperature at which the device, when the temperature is returned to ordinary temperature, is returned to substantially the same piezoelectric characteristic before heating. In the state that the piezoelectric ceramic device is heated, and the temperature is increased, at least one of the piezoelectric phase characteristic and the impedance characteristic of the piezoelectric ceramic device is measured. The measurement is compared with a standard characteristic, whereby an internal defect of the piezoelectric ceramic device is detected, based on results of the comparison. For the heating and temperature-increasing, and the measuring, a high frequency measurement signal having a power level that is higher than the rated level of the piezoelectric ceramic device is applied, and simultaneously with the piezoelectric ceramic device itself being dielectric-heated by the application of the high frequency signal, at least one of the piezoelectric phase characteristic and the impedance characteristic is measured.

Method of inspecting piezoelectric ceramic device

Capacitor characteristics measurement apparatus and packing apparatus includes a turntable ( ) intermittently driven at a constant pitch to supply capacitors (C) from a parts feeder ( ) to a holder section ( ) of the turntable ( ) in a one-by-one manner. A capacitance measurement section ( ) and an IR prediction section ( ) are provided to determine whether each capacitor is acceptable or defective in quality based on the measured values obtainable from these sections ( ). The IR prediction section ( ) applies a DC voltage to a capacitor while predicting the current value at termination of chargeup by use of its initial current value in the charge region of an insulation polarization component thereof upon application of the voltage thereto. A defective product ejection section ( ) is provided for ejecting defective capacitors and an acceptable product extraction section ( ) is provided for putting acceptable capacity into a storage section ( ) of a base material tape ( ) conveyed by a taping device ( ) and then packing the acceptable capacity by a process including a step of pasting a cover tape onto the base material tape ( ).

Capacitor characteristics measurement and packing apparatus

A method for accurately measuring the insulation resistance of a capacitor while reducing time taken for the measurement. To this end, a current calculation equation is first obtained based on an equivalent circuit of a capacitor; then, the calculation equation is modified or corrected based on the degree of coincidence between an actually measured current value m(t) and a calculated current value i(t), the former being within a charge-up region of a dielectric polarization component upon initial application of a voltage; next, the current value at a time point of chargeup termination is predicted or estimated by use of this modified calculation equation.

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Shiga-ken, Japan

Masao Nishimura