Murata Manufacturing Co., Ltd.

Hiroshi Tomohiro

Naoki Fujii

Gaku Kamitani

Keiichi Kami

Taichi Mori

Mikio Nakajima

A measurement error correcting method and electronic component characteristic measuring device capable of accurately coping with an electronic component which includes nonsignal line ports and whose electrical characteristics are changed by a jig. The method includes the steps of measuring an electrical characteristic, with correcting-data-acquisition samples mounted on a test jig enabling measuring nonsignal line ports, and the samples mounted on a reference jig; measuring a through device in which a signal line port and a nonsignal line port are electrically connected to each other; determining a numerical expression for calculating, from results of measurement on the test jig, an estimated electrical characteristic value obtained on the reference jig; measuring an arbitrary electronic component, on the test jig; and calculating the estimated electrical characteristic value obtained on the reference jig.

Measurement error correcting method and electronic component characteristic measurement device

A manufacturing method for a ceramic oscillator capable of controlling the oscillation frequency with a high accuracy is disclosed. In this method, a mother substrate is polarized, electrodes in discrete ceramic oscillator units are formed, the mother substrate is cut into discrete ceramic oscillator units, an outer package is applied to each of the ceramic oscillators, and thus a ceramic oscillator as a finished product is achieved. Herein, the polarization processing for the mother substrate is executed by finishing the application of a high DC voltage, when the antiresonant frequency f of the mother substrate in a thickness vibration mode is measured while the voltage is applied to the mother substrate, and the antiresonant frequency f which is being measured has reached a target value of the antiresonant frequency of the mother substrate during polarization corresponding to a target oscillation frequency of the ceramic oscillator as a finished product.

Manufacturing method for ceramic oscillator

In order to polarize a piezoelectric material in high-temperature gas, a temperature-raising portion raises the temperature of the piezoelectric material to a temperature required to polarize the piezoelectric material. A constant-temperature bath has an atmosphere of the temperature of which is kept at the required temperature, and incorporates a polarizing portion that polarizes the piezoelectric material whose temperature is kept at the required temperature. When the temperature of the piezoelectric material is raised quickly to the temperature required to polarize the piezoelectric material by the temperature raising portion and is placed into the constant-temperature bath, the temperature of the piezoelectric material is at a temperature near a set temperature of the inside of the constant-temperature bath, so that the piezoelectric material can be polarized in a short period of time with high precision.

Polarizing device and method

A DC voltage is applied to a piezoelectric body for polarization treatment in the air and in an atmosphere with a temperature equal to or higher than an aging temperature, and then, the piezoelectric body is aged at the aging temperature. The polarization degree is determined based on the frequency characteristic while the piezoelectric body is polarized. The application of the DC voltage is stopped at the time when the measured polarization degree reaches a set level. The set level is determined based on a correlation between the polarization degree obtained immediately before the application of the DC voltage is stopped and the stable polarization degree obtained after the aging and the ordinary temperature restoration following the stop of the voltage application.

Method of polarization-treating piezoelectric body

A method of polarization-treating a piezoelectric body, which is constructed such that current flows through the piezoelectric body in response to application of a DC voltage to the piezoelectric body, includes the steps of measuring current flowing through the piezoelectric body, and stopping the application of the DC voltage at the time when the measured current value reaches a set level. The polarization degree is controlled based on the current value by utilization of a correlation between the current and the polarization degree during polarization. With this method, a desired polarization degree is obtained, and dispersion of the polarization is reduced.

In a method of polarization-treating a piezoelectric material, the maximum polarization degree &Dgr;f achieved by 180&deg; rotation is determined. A residual polarization degree &Dgr;f as a target value and the maximum polarization degree &Dgr;f are compared. In the case of &Dgr;f&lE;&Dgr;f , a determination is made as to the temperature T for obtaining the polarization degree &Dgr;f made up solely of the polarization degree achieved by 180&deg; rotation. Half-polarization is carried out at the temperature T , and aging is conducted at the temperature T , whereby a piezoelectric material of which the ratio of the polarization achieved by 180&deg; rotation is 100%, which is stable thermally with passage of time, and has a polarization degree &Dgr;f correctly coincident with a target value, can be obtained.

Growing community of inventors

Shiga-ken, Japan

Hiroshi Tomohiro