Patents Assigned to Citizen Watch Company Limited
  • Voltage control system for electronic timepiece
    Patent number: 4328572
    Abstract: In an electronic timepiece powered by a lithium battery, a voltage control system is provided whereby a supply voltage of approximately one half of the battery voltage is supplied to certain portions of the timepiece circuit under normal operating conditions, but whereby cessation of operation by the timebase oscillator circuit of the timepiece due to some abnormal state such as excessively low ambient operating temperature is automatically detected and a changeover is made to supply of the full battery voltage to all of the timepiece circuitry. Upon recovery of operation of the timebase oscillator circuit, changeover to the low voltage supply state is performed.
    Type: Grant
    Filed: August 8, 1980
    Date of Patent: May 4, 1982
    Assignee: Citizen Watch Company Limited
    Inventor: Hisashi Kawahara
  • Electronic timepiece with illumination lamp battery voltage drop compensation circuit
    Patent number: 4328570
    Abstract: In an electronic timepiece having a quartz crystal controlled standard frequency oscillator and a device which temporarily imposes a heavy load on the battery when activated, means are provided for changing a value of a circuit constant in the oscillator circuit, such as capacitance or resistance, when the load device is activated. This change in circuit constant value serves to decrease the value of the minimum battery supply voltage below which the oscillator circuit ceases to function, thereby ensuring reliable operation of the oscillator circuit when the timepiece battery voltage drops due to current being supplied to the load device.
    Type: Grant
    Filed: April 18, 1980
    Date of Patent: May 4, 1982
    Assignee: Citizen Watch Company Limited
    Inventor: Hisahide Nakagawa
  • Decorative plate for a timepiece
    Patent number: 4327428
    Abstract: A dial plate or masking plate for a timepiece, having a pattern formed on a surface of the dial plate by embossing with a mold formed of a hard metal by an electroforming process.
    Type: Grant
    Filed: January 30, 1979
    Date of Patent: April 27, 1982
    Assignee: Citizen Watch Company Limited
    Inventors: Tadao Enomoto, Hiroshi Koide
  • Electronic timepiece providing audible and visible time indications
    Patent number: 4312057
    Abstract: An electronic timepiece is arranged to give an audible time signal indicative of the current time when a user operates an externally manually operable switch means. The operation of the switch means causes a signal emitting means responsive to information relating to the current time to emit a time signal which preferably includes a portion representing a zone within which the current time lies, and a further portion indicative of the current unit of time within the zone. In a preferred embodiment, the signal comprises two parts, one indicating the current hour and the other indicating the current minute.
    Type: Grant
    Filed: December 6, 1978
    Date of Patent: January 19, 1982
    Assignee: Citizen Watch Company Limited
    Inventor: Kazunari Kume
  • Composite display type electronic timepiece
    Patent number: 4312056
    Abstract: An electronic timepiece having a compound display comprising an electro-optical display portion and an analog display portion having time indicating hands and a dial, with the electro-optical display portion being provided by an electro-optical display cell having a central aperture in which at least a portion of the movement of the analog display portion and the analog display dial are accommodated. Information such as seconds indication is provided peripherally around the analog display portion by the electro-optical display portion.
    Type: Grant
    Filed: January 8, 1980
    Date of Patent: January 19, 1982
    Assignee: Citizen Watch Company Limited
    Inventor: Katsuo Nishimura
  • Electronic timepiece
    Patent number: 4308607
    Abstract: An electronic timepiece equipped with a switch means to produce switching pulses in response to actuation of an external operation member, and means for detecting the time intervals between pairs of the switching pulses and producing first control signals indicative of duration of the time intervals. A counter circuit is responsive to the first control signals to provide a second control signal, in response to which a correction signal generation means produces correction signals, the number of which depends on the second control signal.
    Type: Grant
    Filed: April 12, 1979
    Date of Patent: December 29, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Fukuo Sekiya, Minoru Watanabe
  • Electronic timepiece
    Patent number: 4306302
    Abstract: An electronic timepiece equipped with a rotatable operating member which actuates a switch, and means for detecting the direction of rotation of the operating member to utilize a signal produced by the switch for correction of information displayed by the timepiece, the information to be corrected being selected in accordance with the direction of rotation of the operating member.
    Type: Grant
    Filed: March 22, 1979
    Date of Patent: December 15, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Fukuo Sekiya, Minoru Watanabe
  • Electronic timepiece
    Patent number: 4302828
    Abstract: An electronic timepiece includes a frequency supply for providing a relatively high frequency time base signal, a circuit including a frequency converter responsive to the time base signal to provide a relatively low frequency time unit signal, and a time-keeping register responsive to the time unit signal to produce a time information signal. An input means includes an external control to provide an actuation signal when actuated, and an input signal is generated in response to the actuation signal, provision being made for selectively rendering the input signal generating means inoperative. An enabling signal is generated in response to the input signal and the time information signal, and a control responsive to the enabling signal controls the circuit means to correct the time information signal.
    Type: Grant
    Filed: September 15, 1978
    Date of Patent: November 24, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Shigeru Morokawa, Fukuo Sekiya, Yukio Hashimoto, Yasushi Nomura, Keiichiro Koga
  • Electronic timepiece
    Patent number: 4302829
    Abstract: An electronic timepiece includes a primary timepiece circuit unit including a frequency supply for providing a relatively high frequency signal, a frequency converter responsive to the relatively high frequency signal to provide a relatively low frequency time unit signal, timing signals, and a plurality of word pulses indicative of a plurality of data words representing time data concerning the current time, and a set of additional data other than the time data, a timekeeping register arranged to store the time data and the additional data, and display elements for displaying the time data and the additional data. A secondary timepiece circuit unit includes a register arranged to store the additional data to be transferred to the timekeeping register.
    Type: Grant
    Filed: September 15, 1978
    Date of Patent: November 24, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Shigeru Morokawa, Fukuo Sekiya, Yukio Hashimoto, Yasushi Nomura, Keiichiro Koga
  • Matrix driving method for electro-optical display device
    Patent number: 4300137
    Abstract: A matrix driving method for driving an electro-optical display device including digit and segment electrodes arranged in a matrix configuration, in which digit and segment drive signals are applied to digit and segment electrodes in such a manner that the digit drive signals applied to all the digit electrodes have potentials equal in level with each other during a prescribed time interval during which the potential of a first segment drive signal inducing a state of non-display at all the digit electrodes is equal to the potential of each of the digit drive signals.
    Type: Grant
    Filed: July 13, 1979
    Date of Patent: November 10, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Hiroo Fujita, Akira Tsuzuki, Shigeru Morokawa
  • Electronic timpiece
    Patent number: 4298971
    Abstract: An electronic timepiece having voltage regulation, temperature detection and battery voltage detection means provided on the same integrated circuit as is used for timekeeping circuitry, and having external terminals for stepwise weighted adjustment of timekeeping gain/loss.
    Type: Grant
    Filed: January 5, 1979
    Date of Patent: November 3, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Shigeru Morokawa, Keiichiro Koga
  • Watch movement construction
    Patent number: 4296488
    Abstract: A movement construction of a thin, quartz wristwatch with the movement having a thickness less than 2.5 mm, in which a flat coil is adopted as the driving coil of a stepping motor, and a wheel train is disposed in an approximate concentric relationship with said coil.
    Type: Grant
    Filed: June 22, 1978
    Date of Patent: October 20, 1981
    Assignee: Citizen Watch Company Limited
    Inventor: Yasuaki Nakayama
  • Electronic timepiece having an alarm system
    Patent number: 4293939
    Abstract: In an electronic timepiece having an analog type of time display by means of hours and minutes hands, an alarm system is provided which functions electronically and independently of the analog display system. An alarm signal is generated when the time duration counted by an alarm timekeeping circuit coincides with an alarm time stored in an alarm time memory circuit, said alarm time being set by the timepiece user actuating a switch.
    Type: Grant
    Filed: July 5, 1978
    Date of Patent: October 6, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Yasuhiko Nishikubo, Mitsuo Sekine
  • Electronic timepiece
    Patent number: 4292680
    Abstract: An electronic timepiece includes a frequency supply for providing a relatively high frequency time base signal, a frequency converter responsive to the time base signal to provide a relatively low frequency time unit signal, and timekeeping means responsive to the time unit signal to provide current time information. The current time information is corrected and displayed. A calculation command signal is generated and enables a circuit means to produce, in response to the time unit signal, a frequency error signal indicative of an error in the frequency of the time unit signal. A gain/loss adjustment signal is generated in response to the frequency error signal, and a frequency adjusting circuit is provided for adjusting the frequency of the time unit signal in response to the gain/loss adjustment signal.
    Type: Grant
    Filed: September 15, 1978
    Date of Patent: September 29, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Shigeru Morokawa, Fukuo Sekiya, Yukio Hashimoto, Yasushi Nomura, Keiichiro Koga
  • Electronic timepiece
    Patent number: 4290131
    Abstract: An electronic timepiece having time indicating hands driven by a motor through a gear train, and having an analog-to-digital conversion system for time data comprising code disks rotated by the wheel train to provide hours and minutes information in digital coded form, together with means for converting this encoded digital information into digital signals representing hours and minutes information corresponding to the time information indicated by the hands and synchronized with the time indicated by the seconds hand of the timepiece.
    Type: Grant
    Filed: April 4, 1979
    Date of Patent: September 15, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Kazunari Kume, Hideshi Ohno
  • Drive control system for stepping motor
    Patent number: 4283783
    Abstract: In an electronic timepiece having a stepping motor which drives time indicating means, a system is provided for detecting an increase in the load torque on the stepping motor above a predetermined level. When such an increase is detected, the conditions for detection of the load on the stepping motor are changed, and thereafter drive pulses of increased power are applied to the stepping motor. When the increased load is removed, this is detected under the new set of detection conditions, and a return to the original detection conditions is executed, with the drive pulse power being returned to the original level. Stability of control is thereby provided, together with immediate response to increased load on the stepping motor.
    Type: Grant
    Filed: November 21, 1979
    Date of Patent: August 11, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Fumio Nakajima, Takayasu Machida, Kenji Yamada, Fumio Kanno
  • Electronic timepiece
    Patent number: 4282594
    Abstract: An electronic timepiece is equipped with a frequency division ratio adjustment circuit controlled by switch means, for producing a running rate correction signal that is aperiodically added in frequency to the output of a standard frequency oscillator, to correct the running rate of the timepiece, and is provided with externally controlled gate means for inhibiting this aperiodic frequency addition, so that the actual frequency of the standard frequency oscillator may be measured by means such as an external monitoring device which detects a display drive or modulation signal frequency through electrostatic or electromagnetic coupling to the timepiece display.
    Type: Grant
    Filed: December 3, 1979
    Date of Patent: August 4, 1981
    Assignee: Citizen Watch Company Limited
    Inventor: Singo Ichikawa
  • Solar battery timepiece
    Patent number: 4276629
    Abstract: A solar battery timepiece has a structure of a module, a base plate on the module, a solar battery cell on the base plate, an insulating flexible sheet provided with a print wiring and interposed between the base plate and the solar battery cell, and a dial ring attached to the peripheral edge of the base plate whereby the solar battery timepiece may be made with a reduced thickness, small in size, simple in construction, shock resistant and reliable in operation.
    Type: Grant
    Filed: April 27, 1979
    Date of Patent: June 30, 1981
    Assignee: Citizen Watch Company Limited
    Inventors: Osamu Matsumura, Yutaka Kato, Tsunetoshi Sekiguchi, Ryo Namiki
  • Electronic timepiece
    Patent number: 4276628
    Abstract: An electronic timepiece of the type of a so-called analog hand display is disclosed which displays the time by means of hands and is capable of changing the calendar display of a calendar mechanism within very short period of time by means of a reversible motor. Additionally the electronic timepiece is automatically corrected at the end of every month.
    Type: Grant
    Filed: July 25, 1978
    Date of Patent: June 30, 1981
    Assignee: Citizen Watch Company Limited
    Inventor: Yasushi Nomura
  • Module structure for electronic digital timepiece
    Patent number: 4276627
    Abstract: A timepiece module having a liquid crystal display cell, a housing for supporting the liquid crystal display cell, a printed circuit substrate carrying thereon an LSI chip and various electronic components, a battery cell and a cover plate in which said battery cell and LSI chip are disposed on the same side on said printed circuit board.
    Type: Grant
    Filed: February 15, 1979
    Date of Patent: June 30, 1981
    Assignee: Citizen Watch Company Limited
    Inventor: Katsuhiko Komiyama