Sony Corporation

Kazuo Kurihara

Munekatsu Fukuyama

Toru Matsunaga

Yoshinori Satoh

Yasuo Sasaki

Toshiyuki Kawamura

Shigeto Watanabe

Hideo Suyama

Manabu Aizawa

Toshio Aizawa

Yoshihisa Kawamura

Kietsu Iwabuchi

Zenkichi Nakamura

Provided is a vibration gyro sensor including: a vibration element including a piezoelectric element group which has a first side provided with a drive electrode and a detection electrode and a second side opposed to the first side and provided with a common electrode, which vibrates by a drive signal input between the drive electrode and the common electrode and generates an output signal containing a detection signal corresponding to Coriolis force from the detection electrode; a bias section applying a bias voltage to the detection electrode; an oscillation circuit outputting the signal for causing vibration of the vibration element to the drive electrode as the drive signal based on the output signal generated by the detection electrode; and a phase inversion circuit outputting an inversion signal obtained by inverting a phase of the drive signal output from the oscillation circuit to the common electrode.

Vibration gyro sensor, control circuit, and electronic apparatus

A detection apparatus is provided which includes a cantilever vibration gyro including a piezoelectric element having a first side provided with a drive electrode and a pair of detection electrodes sandwiching the drive electrode with predetermined gaps therebetween and a second side opposed to the first side and provided with a common electrode, which vibrates by a drive signal input between the drive electrode and the common electrode and generates a pair of detected signals corresponding to Coriolis force from the detection electrodes. The detection apparatus also includes a bias applying section for applying a bias voltage to the detection electrodes, an adding section adding the pair of detected signals, a first phase delay section delaying a phase of the detected signal obtained by the addition by a range larger than 45&#xb0; and smaller than 90&#xb0;, and an amplitude control section controlling the delayed detected signal to a predetermined voltage amplitude to output as the drive signal.

Detection apparatus, detection method, and electronic apparatus

There is provided an oscillation type gyro sensor including an oscillation gyro device, an oscillation circuit, a controller, and an impedance conversion circuit. The oscillation gyro device includes a piezoelectric device including a drive electrode and a detection electrode, oscillates according to a drive signal input to the drive electrode, and is capable of generating an output signal including a detection signal corresponding to a Coriolis force from the detection electrode. The oscillation circuit outputs, based on the output signal, a signal for oscillating the oscillation gyro device to the drive electrode as the drive signal. The controller controls the oscillation circuit such that the oscillation circuit outputs a drive signal that makes the output signal constant. To the impedance conversion circuit, the drive signal output from the oscillation circuit is input.

Oscillation type gyro sensor, control circuit, electronic apparatus, and method of manufacturing an oscillation type gyro sensor

Vibration gyro circuitry, a vibration gyro unit, and a method for detecting a vibration gyro output, which enable detection of a rotational angular velocity with high sensitivity, are provided. The circuitry and the unit includes a differential amplifier circuit () for outputting a signal Vda corresponding to a difference (Vgl&#x2212;Vgr) between output signals of two detection pieces of a vibration gyro (), a synchronous detection circuit () for synchronously detecting the output signal Vda of the differential amplifier circuit (), and a phase shift circuit for supplying to the synchronous detection circuit () a signal, as a timing signal Vck for the synchronous detection, which is phase-shifted with respect to a drive signal (an output signal of an adding circuit) Vsa supplied to the vibration gyro (). The phase difference &#x3b8;ps between the drive signal Vsa and the timing signal Vck is set on the basis of a phase difference characteristic of a detection sensitivity S for the output signal Vda of the differential amplifier circuit (), which is obtained in advance under a condition where a rotational angular velocity is applied to the vibration gyro () in a driving state.

Vibration gyro circuitry, vibration gyro unit, and method for detecting vibration gyro output

The present invention provides a drive circuit of an oscillation gyro including two piezoelectric elements formed in an oscillator, which includes an adding circuit for supplying a drive signal to one side faces of the two piezoelectric elements and adding signals obtained from the other side faces opposed to the one side faces of the piezoelectric elements, and an oscillation circuit adapted to be fed back with an addition output signal obtained by the adding circuit, wherein a sine wave signal obtained as an oscillation output of the oscillation circuit is supplied to the one side faces of the two piezoelectric elements as the drive signal. Thus, the drive circuit of the oscillation gyro which obtains the stable output with the simple configuration can be provided.

Drive circuit of oscillation gyro

An angular rate sensor includes: a quadratic prism-like oscillatorformed by laminating a substrateand a piezoelectric material; a reference electrodewhich is formed on one main surfaceA of two opposed surfaces of the piezoelectric material, the one main surfaceA being bonded to the substrate, and which is connected to a reference potential; at least one drive electrodewhich is formed on the other main surfaceB of the two opposed surfaces of the piezoelectric materialin the longitudinal direction of the oscillator, and to which a signal for oscillating the oscillatoris supplied; and at least a pair of detection electrodesandwhich are formed, in parallel with each other, on the other main surfaceB of the two opposed surfaces of the piezoelectric materialin a manner to sandwich the drive electrode, and which output a signal corresponding to Coriolis force generated in the oscillator

Angular rate sensor

An angular rate sensor includes a quadratic prism-like oscillatorformed by laminating a substrateand a piezoelectric material, the piezoelectric materialis made of piezoelectric ceramics including PZT (Lead Zirconate Titanate) as a main component, and the substrateis made of a material other than PZT having physical property values equivalent to or less than PZT, which is a main component of the piezoelectric ceramics, with respect to Young's modulus, thermal expansion coefficient, and the like.

Band gap reference circuit

A geomagnetic direction sensor has a plurality of magnetic cores for converging terrestrial magnetism arranged circumferentially with pre-set gaps, and magneto-resistive effect devices in the gaps so as to lie substantially at right angles to the direction of the magnetic field in the gaps. The geomagnetic direction sensor has at least a pair of magneto-resistive effect devices lying substantially at right angles to each other. The magnetic core is formed of a magnetic material having soft magnetic properties. The current is supplied to the excitation coils placed around the magnetic core for applying a bias magnetic field to the magneto-resistive effect devices. Another set of magneto-resistive effect devices are connected in series with the magneto-resistive effect devices arranged within the gap so as to be substantially parallel to the direction of the magnetic field.

Geomagnetic direction sensor

A recording/reproducing apparatus for a magneto-resistive (MR) head having a playback amplifier, including a capacitor for a dc feedback low-pass filter for do feedback to an initial-stage transistor, and a differential amplifier (gm amplifier), and a switching device for the gm amplifier and for the initial-stage amplifier operable at the time of recording/playback switching. The timing of the switching device is deviated for shortening the switching time interval. To this end, an output of the initial-stage transistor of a playback amplifier for a MR head is compared to reference voltage Vref by a gm amplifier and the low-pass filter is constituted by transconductance gm of the gm amplifier and the capacitance of the capacitor, with the dc output of the gm amplifier being fed back to the base of the initial-stage amplifier. The delay in switching time by the charging of the capacitor caused by the difference in the rise time of the initial-stage transistor and the gm amplifier is deviated by the control signal from a control circuit to control the initial-stage transistor and the gm amplifier.

Reproducing circuit for a magnetic head having a variable gain amplifier

A recording/reproducing apparatus for a magneto-resistive (MR) head having a playback amplifier, including a capacitor for a dc feedback low-pass filter for dc feedback to an initial-stage transistor, and a differential amplifier (gm amplifier), and a switching device for the gm amplifier and for the initial-stage amplifier operable at the time of recording/playback switching. The timing of the switching device is deviated for shortening the switching time interval. To this end, an output of the initial-stage transistor of a playback amplifier for a MR head is compared to reference voltage Vref by a gm amplifier and the low-pass filter is constituted by transconductance gm of the gm amplifier and the capacitance of the capacitor, with the dc output of the gm amplifier being fed back to the base of the initial-stage amplifier. The delay in switching time by the charging of the capacitor caused by the difference in the rise time of the initial-stage transistor and the gm amplifier is deviated by the control signal from a control circuit to control the initial-stage transistor and the gm amplifier.

Reproducing circuit for a magnetic head incorporating the

A magnetic detection apparatus is disclosed, the size and cost of which can easily be reduced and with which excellent sensitivity can be obtained. The magnetic detection apparatus according to the present invention has a magnetic sensor formed by winding a coil around a magnetic member, wherein change in a response waveform of an electric current allowed to flow in the coil of the magnetic sensor occurring when time-varying voltage is applied to the coil is detected. Since the response waveform of the electric current allowed to flow in the coil is changed in accordance with the intensity of an external magnetic field, the external magnetic field can be detected.

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Saitama, Japan

Kazuo Kurihara