Seiko Instruments Inc

Satoshi Sakai

Tomohiro Ihashi

Kenji Ogasawara

Kazumi Sakumoto

Kazuo Kato

Keisuke Tsubata

Kosuke Yamamoto

Eriko Noguchi

Hisao Nakamura

Yoshinori Sugai

Katsuya Mugishima

Akira Takakura

Saburo Manaka

Keishi Honmura

Takanori Hasegawa

Tetsuya Nobe

Akihiro Iino

Toshitaka Fukushima

Akihito Okumura

Shotaro Kamiyama

Yukio Akiyama

Takuo Oosaki

Masakazu Hirabayashi

Masatomo Moriko

A motor driving apparatus including a driving circuit for supplying a first pulse with which a first coil included in a two-phase stepping motor generates a first magnetic flux, a second pulse with which a second coil included in the stepping motor generates a second magnetic flux opposite to the first magnetic flux, a third pulse with which the first coil generates the second magnetic flux, and a fourth pulse with which the second coil generates the first magnetic flux, to the stepping motor. The driving circuit supplies the second pulse, the third pulse, and the fourth pulse in this order to the stepping motor in a state of being stopped to start the stepping motor, and supplies the first pulse, the second pulse, the third pulse, and the fourth pulse in this order to the stepping motor after starting to continuously drive the stepping motor.

Motor driving apparatus, motor driving method, and timepiece

A timepiece includes a stepping motor having a rotor and a coil, and a drive circuit that applies a first drive pulse having a stable stationary position at a rotor rotation angle of 90 degrees or less from a reference position and a second drive pulse having the stable stationary position at a rotor rotation angle of 90 degrees or more from the reference position, as a pulse for driving the rotor, to the coil. When a period during which the pulse is not applied to the coil is assumed as a waiting period, the drive circuit generates the waiting period after a first application of the second drive pulse after an application of the pulse to the coil is started and rotates the rotor by one or more turns without passing through the waiting period at at least one predetermined timing after the waiting period.

Timepiece and motor control method

A timepiece capable of selecting a timepiece mode and a chronograph mode includes an hour hand and a minute hand which indicate current time in a case where the timepiece mode is, selected. A main control unit performs control so as to start measuring time by simultaneously starting hand operations of the hour hand and the minute hand in a case where the chronograph mode is selected. When the hand operation of one of the hands is stopped, the control unit performs control so as to indicate the time when the hand operation of the one hand is stopped, and to continue to measure the time by continuing the hand operation of the other hand.

Timepiece

A power saving movement includes a center wheel and pinion driving a minute hand and minute detection wheel. A gear ratio of the center wheel/pinion with respect to the minute detection wheel is 1/M. The minute detection wheel has N minute detection portions which are disposed on the same rotation trajectory as the center wheel & pinion. N and M are integers. The minute detection wheel transmittable portions are disposed at an interval of 360&#xb0;/N. A pair of the center wheel transmittable portions are disposed in parallel at an unequal angular interval of a center axle of the center wheel & pinion. An angular interval of the center wheel transmittable portions adjacent to each other in the circumferential direction of the center axle of the center wheel & pinion is set to magnification of 360&#xb0;/(M&#xd7;N).

Movement and electronic timepiece

A timepiece movement includes a second light emitting element, a second light receiving element, and a second wheel & pinion that drives a second hand and that has a first second wheel transmittable portion and a second second wheel transmittable portion through which light is transmittable, A control unit detects a position of the second wheel & pinion by causing the second light receiving element to receive the transmitted light emitted from the second light emitting element and transmitted through the first second wheel transmittable portion or the second second wheel transmittable portion, and a second detection wheel has a second detection wheel transmittable portion through which the transmitted light is transmittable. The control unit detects a transmitting time point at which the transmitted light is transmitted through the first second wheel transmittable portion or concurrently through the second second wheel transmittable portion and the second detection wheel transmittable portion. After the transmitting time point, when the second detection wheel transmittable portion is located at other positions except for a second detection position where the second detection wheel transmittable portion is located at the transmitting time point, the control unit causes the second light emitting element to stop light emitting.

A timepiece movement includes a center wheel & pinion that drives a minute hand, a second wheel & pinion arranged coaxially with a center axle of the center wheel & pinion, a first light emitting element arranged on one side in an axial direction of the center axle with respect to the center wheel & pinion and the second wheel & pinion, and a first light receiving element arranged on the other side in the axial direction of the center axle across the second wheel & pinion, and that detects light emitted from the first light emitting element. The center wheel & pinion has a first center wheel transmittable portion through which the light emitted from the first light emitting element is transmittable, and a second center wheel transmittable portion which is disposed on a rotation trajectory of the first center wheel transmittable portion and through which the light emitted from the first light emitting element is transmittable. The second wheel & pinion has a first second wheel transmittable portion which is disposed on the rotation trajectory of the first center wheel transmittable portion and the second center wheel transmittable portion when viewed in the axial direction of the center axle and through which the light emitted from the first light emitting element is transmittable.

A rotation detection circuit detects an induced current flowing through a drive coil of a stepping motor in a detection section divided into a plurality of sections, and detects a rotation state of the stepping motor on the basis of a pattern indicating whether or not the induced current exceeds a predetermined reference value in each of the sections. A control unit selects a drive pulse corresponding to the rotation state detected by the rotation detection unit, and supplies a drive current to a drive coil to rotatably drive the stepping motor. The rotation detection unit carries out detection by selecting a detection direction of the induced current in the sections after the first section on the basis of whether or not the induced current exceeding each of a plurality of reference values is detected plural times in the first section.

Stepping motor control circuit, movement, and analog electronic timepiece

A stepping motor control circuit includes: a rotation detection unit that detects a induced signal exceeding a predetermined reference threshold voltage which is generated by a stepping motor in a detection section divided into at least three sections, and detects a rotation state on the basis of a pattern indicating whether the induced signal exceeding a reference threshold voltage is detected in each of the sections; and a control unit that selects a main drive pulse depending on the rotation state detected by the rotation detection unit from a plurality of main drive pulses which are different from each other in energy, and drives the stepping motor. When the induced signal exceeding a reference threshold voltage is not detected in an initial section, the rotation detection unit detects the induced signal by shifting an end position of at least one section other than the initial section to a rear side by a predetermined amount.

Stepping motor control circuit, movement and analog electronic timepiece

A display device includes independently driven common and segment terminals. The common and segment terminals are connected to display components divided into display blocks that are turned ON to perform a display function and are turned OFF so as to not perform the display function. A first driver drives the common terminals using a scanning signal of a predetermined period and a second driver drives the segment terminals using a segment signal synchronized with the scanning signal to correspond to a display signal, so that the display components perform a display corresponding to the display signal. The first driver separates the common terminals into common terminal blocks and drives the common terminals. The first and second drivers perform the driving so that the common and segment terminals which are connected to display blocks that are turned OFF are not supplied with a turn-off signal and are maintained at ground potential.

Display device and electronic apparatus using display device

A power supply unit has a first power supply circuit that supplies a voltage to a load driving unit and a second power supply circuit that supplies a voltage to circuits other than the load driving unit. A first switching unit connects any one of a power supply that supplies a power supply voltage and a voltage step-down circuit that supplies a step-down voltage of the power supply voltage to the first power supply circuit. A second switching unit connects any one of the power supply and the voltage step-down circuit to the second power supply circuit. A control unit controls the connection by the first switching unit and the connection by the second switching unit to switch the voltage supplied to the first power supply circuit and the voltage supplied to the second power supply circuit in accordance with properties of the load driving unit.

Power supply unit and electronic timepiece

An ultrasonic motor exhibits stable performances by suppressing irregularities of magnitudes of two standing waves excited by a piezoelectric element. A plurality of divided electrodes are mounted on one surface of the piezoelectric element and are equidistantly arranged in the circumferential and radial directions and have equal polarized areas. Alternate ones of the divided electrodes are short-circuited in the radial direction by inner electrodes arranged on the inner peripheral side of the divided electrodes, and the other alternate ones of the divided electrodes are short-circuited in the radial direction by outer electrodes arranged on the outer peripheral side of the divided electrodes.

Ultrasonic motor and electronic apparatus which mounts the motor thereon

The ultraviolet ray sensor measures the intensity of ultraviolet rays irradiated to the ultraviolet ray receiving surface. The CPU performs control to measure ultraviolet intensity in a case in which the ultraviolet ray receiving surface of the ultraviolet ray sensor faces in a predetermined direction.

Growing community of inventors

Chiba, Japan

Satoshi Sakai