Citizen Watch Company, Ltd.

Citizen Holdings Company, Ltd.

Yoichi Nagata

Shigeru Watanabe

Tomomi Murakami

Makoto Watanabe

Takashi Ihara

Akiyoshi Murakami

Hisato Hiraishi

Yasuo Kamiyama

Akira Shiota

Akira Izumi

Masao Mafune

Tohru Yanagisawa

Isao Arai

Motoki Funahashi

Masahiko Hitomi

An electrostatic induction generator includes a housing, a first board fixed to the housing, and a second board arranged in parallel to the first board to be able move relative to it, in which electrostatic induction generator, counter electrodes are placed at a first facing surface of the first board, electrically charged films are placed at every other constant interval at a second facing surface of the second board so as to face the counter electrodes, the counter electrodes are comprised of pluralities of first electrodes and second electrodes provided separated from each other at the first facing surface, first electrodes and second electrodes are alternately arranged at constant intervals in a single line, a plurality of lines of single lines of the first electrodes and second electrodes are provided at the first facing surface, and the constant intervals of the plurality of lines respectively differ in phase.

Electrostatic induction generator

Provided is a technology capable of preventing arithmetic operation accuracy from deteriorating even when a bipolar transistor used to form a Gilbert multiplier core has poor characteristics. A correction current generating circuit () uses a constant current source () to feed a constant current Ito an emitter of a bipolar transistor (Q7) being a first replica transistor having the same current gain &#x3b1; as bipolar transistors (Q1 to Q4) that form the Gilbert multiplier core (), to generate a current of &#x3b1;&#xb7;Ion a collector side thereof. The current is output as a correction current &#x3b1;&#xb7;I, and is added to each of one of input signals (&#xb1;K1&#xb7;Vy) of the Gilbert multiplier core () as a bias current, to thereby eliminate influence of the current gain &#x3b1; on an output signal being a multiplication result.

Analog multiplier circuit, variable gain amplifier, detector circuit, and physical quantity sensor

A physical quantity sensor includes a sensor element that converts an externally applied physical quantity to an electrical signal; a detection circuit that amplifies and detects the output signal of this sensor element; and an adjustment circuit that adjusts the output signal from the detection circuit to a predetermined signal by applying the power supply wherein the adjustment circuit comprises an amplifier circuit that amplifies the output signal from the detection circuit and a reference amplifier circuit that has a gain that is made to correspond to the gain of the amplifier circuit. This configuration allows the gain of the amplifier circuit in the adjustment circuit to be varied according to the power supply voltage and, as a results, provides a physical quantity sensor having reliable sensor detection sensitivity and high-accuracy ratiometric characteristics.

Physical quantity sensor

A physical quantity sensorcomprises a driving circuitthat drives a sensor element based on a reference signal; the sensor elementthat is driven by the driving circuitto convert an externally applied physical quantity to an electrical signal; and an amplifier circuitthat amplifies an output signal of the sensor element. The driving circuitcontrols a driving signal, which drives the sensor element, based on the reference signal so that the driving signal is at a fixed level, and the amplifier circuithas a gain characteristic that amplifies the output signal in a direction reverse to a direction in which the reference signal varies or the driving signal of the driving circuit varies. This configuration allows the physical quantity sensor to reduce output level variations in the sensor output against signal level variations in the reference signal and to make the sensitivity constant.

A vibration body for angular speed sensor has a vibrator that includes vibration pieces, a supporting part for supporting the vibration pieces, and a mounting substrate for mounting the vibrator. The mounting substrate has a seat part for fixing the supporting part and supporting the vibrator and a base part. The seat part has a level difference representing a predetermined height from the base part. The predetermined height is set larger than an oscillation width of the vibration pieces. The seat part also has an edge portion that has a shape of a curved line, and each line in a direction perpendicular to each position on the edge portion determines a mounting angle for mounting the vibrator and has an angle in the same direction as a reference direction defined in the mounting substrate or in a direction at least one being different from it.

Vibration body for angular speed sensor

A physical quantity sensor comprises a sensor circuit that converts an externally applied physical quantity to an electrical signal and outputs a detection signal; an adjustment circuit that adjusts the detection signal, which is received from the sensor circuit, to a predetermined signal; and an output circuit that forms an output signal from the signal of the adjustment circuit wherein the sensor circuit and the output circuit are driven by a common power supply voltage. The adjustment circuit comprises a pulse generation circuit that generates a pulse modulation signal based on the power supply voltage; and an amplifier circuit that amplifies the detection signal, which is received from the sensor circuit, with a gain made variable by the pulse modulation signal, wherein the detection sensitivity of the output signal is made variable according to the power supply voltage. This configuration enables the amplifier circuit, provided in the adjustment circuit, to output a sensor output that has high linearity characteristics and, as a result, implements a physical quantity sensor with highly accurate sensor detection sensitivity and allows the physical quantity sensor to have good detection-sensitivity ratiometrics characteristics, high linearity, and desired-characteristic detection sensitivity.

The invention provides a rechargeable electronic timepiece that restarts the operation of a clock circuit by inputting a power source, thereby securely confirming the clock operation. The electronic timepiece includes a first power source (), a clock circuit () connected to the first power source, a power source input detecting circuit () for detecting an input of a second power source (), a switch circuit () for connecting the first power source and the second power source, and a control circuit () for controlling the switch circuit to connect the first power source and the second power source so that the first power source is charged by the second power source thereby operating the clock circuit when the power source input detecting circuit detects an input of the second power source.

Electronic clock

Using an oscillating unit () that can start oscillation with a low voltage, an oscillation signal (S) of the oscillating unit () is amplified via a waveform shaping unit (), and is fed to a boosting control unit (). A boosting unit () is caused to perform a boosting behavior by a boosting clock (Sa) with the same frequency as an oscillation frequency of the oscillation signal (S) just after the oscillating unit () starts. Thereby, a whole electronic timepiece () can be self-actuated, even if a generation voltage is low. Further, the oscillating unit () is constituted such that a operating current always becomes constant. Thereby, the electronic timepiece can be provided with an electricity-generating unit () such as a solar cell with a one-stage constitution having a low open voltage.

Electronic timepiece

An electronic timepiece comprises power generation means for generating electricity by using external energy, storage means for storing electric energy received from the power generation means, time-indicating means powered by electric energy supplied from the power generation means or the storage means for indicating time, a switch circuit including a plurality of switching devices and adapted to transfer or intercept electric energy between the power generation means and the storage means and between the power generation means and the time-indicating means, voltage measuring means for measuring voltage across the time-indicating means, and control means that selects one of predetermined power ratios based on the results of measurement by the voltage measuring means and controls the switch circuit according to the selected ratio when the power generation means charges the storage means and the time-indicating means.

An electronic timepiece is controlled such that, when an amount of the actual capacity that remains in storage means thereof is found to be less than a predetermined amount as a result of measurement of a voltage between the terminals of the storage means by voltage measurement means , all electrical discharge paths from the storage means to timing means and an electric power generator are completely shut off by the agency of charge/discharge control means , thereby preventing occurrence of wasteful over-discharge from the storage means . As a result, upon resumption of power generation by the electric power generator , entire electric energy generated can be effectively utilized, so that the restart of a time-keeping operation by the timing means is speeded up, and the operation thereafter is stabilized.

Electronic clock and method of controlling the clock

An electronic timepiece is formed of a power generating device for generating power, a control device for driving on receipt of a power supply from the power generating device, a display device for displaying a time by an operation of the control device, a detecting device for detecting a state of the power generating device, and a deciding device for deciding whether or not the power generating device generates power based on a detection signal sent from the detecting device. The control device controls such that a power generating state of the power generating device is displayed on the display device based on a decision of the deciding device. It is possible to reduce power consumption by stopping hands if required.

Electronic timepiece having power generating function

In order to optimally control supply of electric power to a load means and efficiently utilize generated energy of a thermoelectric power generator in consideration of influence of the Peltier effect against generated voltage of the thermoelectric power generator, a thermoelectric system is structured by connecting a load means (,) utilizing the generated power of the thermoelectric power generator (,), and a controller (,) for measuring the generated voltage (V,) of the thermoelectric power generator (,) and controlling power supply and suspension of the power supply to the load means (,) in accordance with the measured result to the thermoelectric power generator (,) provided with a plurality of thermocouples electrically in series, and a compensating means to perform measurement with compensating for the generated voltage when power is supplied from the thermoelectric power generator (,) to the load means (,) continuously for more than a predetermined period of time, is provided to the controller.

Thermoelectric system

A switch means (,) consisting of plural switching elements, which switches the connection relationship, is provided between a pair of power generating terminals (g,, g,) of a power generator (,) and a pair of output terminals (e,, e,), to apply the output voltage to a load means (,) so as to utilize the generated power, at the same time voltage of the output terminals is measured with a switch-output measuring means (,), and a controller (,) controls the connection relationship between input and output terminals of the switch means (,) in response to the measured result to output the voltage having polarity required by the load means (,) from the output terminals (e,, e,) continually.

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Saitama, Japan

Yoichi Nagata