Citizen Watch Company, Ltd.

Citizen Holdings Company, Ltd.

Toshinari Maeda

Toshiaki Fukushima

Daisuke Iri

Yu Takyoh

Daisuke Matsuoh

Akira Shiota

Masatoshi Nishida

Makoto Watanabe

Nobuaki Suzuki

Izumi Yamamoto

Yasuo Kitajima

Akira Izumi

Yu Takyo

Shogo Kimura

An electronic watch includes a power source, an electrostatic motor including a rotor in which a plurality of electret films are arranged in a rotational direction and a plurality of fixed electrodes arranged in the rotational direction at positions facing the rotor, a hand rotating in conjunction with the rotation of the rotor, and a motor control circuit controlling the electrostatic motor. The motor control circuit selectively executes a hand movement mode for rotating the hand and a stop mode for keeping the hand stationary. In the stop mode, the motor control circuit keeps the rotor stationary through electrostatic forces exerted on the electret films from the fixed electrodes with the polarities of the fixed electrodes maintained.

Electronic watch

An electronic watch with a two-coil stepper motor including: a magnetized rotor; a stator including: first and second stator magnetic-pole portions, which are formed so as to oppose to each other through the rotor; and a third stator magnetic-pole portion, which is formed between the first stator magnetic-pole portion and the second stator magnetic-pole portion so as to face the rotor; a coil A to be magnetically coupled to the first stator magnetic-pole portion and the third stator magnetic-pole portion; and a coil B to be magnetically coupled to the second stator magnetic-pole portion and the third stator magnetic-pole portion; and a high-speed drive pulse generation circuit configured to output a drive pulse for driving the rotor to the coil A or the coil B, and wherein the rotor is rotationally driven in increments of 360&#xb0; due to a drive pulse train formed of the plurality of drive pulses.

Step motor drive device and circuit

Provided is a small-sized electrostatic motor having a rotor capable of starting reliably to rotate forward. The electrostatic motor includes a rotor rotatable around a rotating shaft, charged portions formed radially around the rotating shaft on upper and lower surfaces of the rotor, first and second stators disposed to sandwich the rotor therebetween, and first sets and second sets of fixed electrodes respectively formed radially around the rotating shaft on the surfaces of the first and second stators facing the rotor and selectively energized according to drive pulses to rotate the rotor by electrostatic force generated between the charged portions and the fixed electrodes. The average number of sets of fixed electrodes simultaneously energized in one cycle of the drive pulses out of the first sets and second sets of fixed electrodes is equal to the average of the numbers of first sets and second sets of fixed electrodes.

Electrostatic motor

Provided is a method of manufacturing an electrostatic induction transducer, the method including: providing a conductive substrate; providing a first electret material film on a first surface of the conductive substrate; providing a second electret material film on a second surface of the conductive substrate; forming a through hole that penetrates the conductive substrate, the first electret material film, and the second electret material film; mounting a supported member being conductive to the conductive substrate while allowing the conductive substrate to move in an in-plane direction; and applying charges to the first electret material film and the second electret material film by a charging process.

Method of manufacturing an electrostatic induction transducer, electrostatic induction transducer, and wristwatch

Provided is a drive circuit for a two-coil stepper motor, including: a rotor; a stator including first, second, and third stator magnetic-pole portions; a coil A to be magnetically coupled to the first stator magnetic-pole portion and the third stator magnetic-pole portion; a coil B to be magnetically coupled to the second stator magnetic-pole portion and the third stator magnetic-pole portion; a drive pulse generation circuit configured to output a drive pulse; a detection pulse generation circuit configured to output a detection pulse for detecting counter-electromotive currents generated in the coil A and the coil B; and a rotation detection circuit configured to receive a detection signal generated due to the detection pulse as input to determine whether or not the rotor has rotated.

Drive circuit for two-coil step motor

Drive circuit for two-coil step motor, two-coil step motor, and electronic watch using these

Provided is a drive circuit for a two-coil stepper motor, including a rotor that is magnetized to an N-pole and an S-pole, first, second, and third stator magnetic-pole portions, a coil A, and a coil B. The drive circuit includes a drive pulse generation circuit configured to output a drive pulse (SP) for driving the coil A and the coil B, a detection pulse generation circuit configured to output a detection pulse (CP) to the coil A and the coil B in order to detect counter-electromotive currents generated in the coil A and the coil B along with a movement of the rotor after the rotor is driven based on the drive pulse, and a detection circuit configured to receive a detection signal (CS) generated based on the detection pulse as input, to thereby detect the movement of the rotor. At least one of the detection pulse to the coil A or the detection pulse to the coil B is output.

An oscillating stepping motor can reduce a required rotational angle of a rotor to drive a star wheel, reduce idle driving, cut the loss of energy required for the driving, reduce power consumption even in high-frequency driving, and stably operate. Two star wheels are located so that the tooth tips thereof are not engaged with each other. A rotor shaft includes a rotor pinion having two feed teeth at a certain aperture angle. One of the feed teeth feeds one of the driving wheels by oscillation of the rotor in one direction and the other of the feed teeth feeds the other of the driving wheels by the oscillation of the rotor in the other. The rotor then oscillates within a certain angle range, thereby sequentially rotating output gears in a certain direction by a certain angle.

Wrist watch oscillating step motor with sweep motion

Provided is an electronic watch capable of, even if an indicating hand having a large moment of inertia is used, accurately determining success and failure of rotation. The electronic watch detects rotation by using a first detection mode determination circuit () and a second detection mode determination circuit (). In the electronic watch, a timing counter () for measuring a time after an output of a normal drive pulse is followed by a detection pulse selection circuit () provided as changing means for changing a width or a frequency of a detection pulse in accordance with an output time of the detection pulse. The detection pulse detects the rotation and simultaneously serves as an electromagnetic brake for a rotor (). The electromagnetic brake for the rotor () is controlled by changing the width or the frequency of the detection pulse in a predetermined period, thereby achieving an accurate rotation detection. Alternatively, the setting of the width or the frequency of the detection pulse may be changed in accordance with a determination result in a first detection mode, an output voltage of a power supply, and a driving power of the normal drive pulse, instead of the output timing of the detection pulse.

A magnetic drive apparatus, which has a rotor; and a stator having a stator magnetic flux generator, and a stator magnetic guidepath for guiding magnetic flux from the stator magnetic flux generator to the rotor, and which rotationally drives the rotor relative to the stator by controlling the flow of the magnetic flux of the stator magnetic flux generator, the magnetic drive apparatus being constituted such that it further has magnetic flux controlling means, which is respectively stacked onto and bridges the rotor side end tip of the stator magnetic guidepath and a magnetic pole tip which is arranged at a prescribed angular location on the periphery of the rotor with a first gap with this end tip part, and magnetic flux controlling means has a function for magnetically reconnecting to the magnetic pole tip after controlling the flow of magnetic flux, which is blocked by the first gap. Consequently, there is no need for an excitation coil, power consumption is lowered by reducing the consumption of energy due to the copper loss of the excitation coil and so forth, and the driving apparatus can be made smaller, thinner and less expensively regardless of coil diameter.

Magnetic drive apparatus

A magnetic drive apparatus including a rotor with a rotor magnetic flux generator, a stator with a stator magnetic flux generator and stator magnetic paths, and a magnetic flux controller provided in intermediate positions in said stator magnetic paths for controlling a magnetic flux flowing through the stator magnetic paths.

Growing community of inventors

Tokorozawa, Japan

Toshinari Maeda