Citizen Watch Company, Ltd.

Makoto Yoshida

Masamichi Yamauchi

Yoshifumi Mochizuki

Shigeru Morokawa

Fuminori Suzuki

Yasuaki Nakayama

Hideyuki Kawashima

Tetuya Yasuda

Yoshinobu Kashima

Mituo Oooka

Shinichi Watanabe

Choken Suzuki

An electronic timepiece having a quartz crystal oscillator circuit as a timebase signal source is provided with a temperature compensation system to compensate timebase signal frequency deviations with temperature, all components of the system being incorporated in the timepiece IC chip. The system is based on a temperature-sensitive voltage stabilizer circuit whose output voltage is current-converted to control the frequency of a temperature-insensitive oscillator circuit. Date generated on the basis of the latter oscillator frequency is applied to compensate the timebase signal frequency, by a capacitor switching technique.

Electronic timepiece with temperature compensation

An electronic timepiece is provided with a timebase signal source comprising a relatively low frequency quartz crystal oscillator circuit and with means for compensating the timebase signal frequency for the effects of temperature changes on the low frequency oscillator circuit, and further with means for comparing the timebase signal frequency with the frequency of a relatively high frequency quartz crystal oscillator circuit having high stability against aging changes, to thereby compensate for changes in the timebase frequency caused by aging of the low frequency quartz crystal vibrator, this comparison being carried out only within a specific narrow range of operating temperatures.

Electronic timepiece

A digital electronic timepiece which comprises an oscillator circuit providing a relatively high frequency signal, a frequency divider dividing down the relatively high frequency signal to provide a first low frequency signal representative of the count of one second and a second low frequency signal higher in frequency than the first low frequency signal and representative of the count less than one second, a first counter responsive to the first low frequency signal to provide time and calendar information signals; and an additional data signal a second counter responsive to the second low frequency signal to provide output signals representative of the count less than one second, first display means for displaying time and calendar data in response to the time and calendar information signals, second display means composed of a plurality of display segments for displaying data representative of the count less than one second in step-wise fashion in response to the output signals from the second counter, said display segments serving as means for displaying additional data, and switching means for enabling said second display means to display said additional data.

Digital electronic timepiece

A solar cell battery charging control system having a storage battery and a plurality of solar cells connected in series for charging the storage battery, which system comprises a heavy load means adapted to be driven by the storage battery to discharge the storage battery for thereby preventing overcharging of the storage battery when a battery charge level exceeds a predetermined value.

Solar cell battery charging control system

An electronic timepiece equipped with an oscillator for producing a time base, a freuqency divider and time display means drive in response to output signals supplied by the frequency divider, which timepiece includes correction system characterized in that a single switch is provided for rapidly correcting the time display means, wherein time corrections are alternatively accomplished in an advancing and retarding direction each time the switch is depressed.

Electronic timepiece correction device

An integrated circuit comprises components for the basic functions of a timepiece and additional components for controlling the operation mode of the basic components. By properly controlling the operation mode of the basic components, the integrated circuit can be applied to two or more types of timepieces, thereby reducing the kinds of the integrated circuits that need to be prepared.

Integrated circuit for timepiece

An electronic timepiece having a multi-digit display of time data and a plurality of frequency divider circuits which generates time data, which comprises operation testing and time correcting means including at least two test terminals, and also a manually operable selecting switch and a manually operable correcting switch. The electronic timepiece also comprises a circuit means which is arranged such that varying combinations of logic level voltages applied to the test terminals can be utilized to test various modes of operation of the frequency divider circuits, a part of such testing being accomplished in conjunction with a signal of relatively high frequency applied to a terminal of one of the manually operable switches.

Electronic timepiece and method for testing operation of the same

A liquid crystal display driver control circuit device comprising a control circuit turning on and off a display cell between an alternating current voltage supply source and the input of a liquid crystal driver circuit and said control circuit controlling the display of at least one digit figure or mark by means of a small number of elements.

Drive control for drive circuit of liquid crystal display

An electronic timepiece having a frequency standard, a frequency divider which divides an output frequency of the frequency standard to provide output pulse signals, a time counter driven by the output pulse signals from the frequency counter, and display means for displaying the contents of the time counter, in which a counter means is coupled to the time counter to form a serial counter chain and receiving an output signal from the time counter to perform a plurality of functions, and a change-over means is disposed in the counter chain between the time counter and the counter means, the change-over means selectively changing over the functions of the counter means.

An adjustable circuit for an electronic timepiece including a crystal oscillator, a frequency divider circuit, a display and a controlable means for increasing and decreasing the output frequency of the frequency divider circuit. The increasing and decreasing means includes a digital adder and a digital subtractor and a plurality of controlable gates for enabling the digital adder or subtractor to increase or decrease the output frequency of the frequency divider.

Adjustable circuit for an electronic timepiece

An electronic wristwatch with an electronic sound emitter device which provides greatly improved efficiency in the quality and quantity of the sound emitted with a minimum number of elements. The results, in general, are obtained by arranging the elements in such a manner that a suitable signal is presented to the sound emitter driving device upon the coincidence of a preset time and the time given by a time display device.

Electronic wristwatch with electronic sound emitter device

An electronic watch having an illuminating time display is provided with a switch for controlling the illumination which is operable controlled movement of the arm on which the watch is carried. A closed casing in the watch is provided with electrical contacts and a ball which will engage the contacts to close the watch upon predetermined movement of the arm.

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Tokorozawa, Japan

Makoto Yoshida