Patents by Inventor Hiro Fujita

Hiro Fujita has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4465999
    Abstract: A method of cyclically driving an electro-optical display device having a matrix array of a plurality of row electrodes and a plurality of column electrodes, wherein said column electrodes intersect with said row electrodes to provide a plurality of display elements at intersections between said row and column electrodes, comprising the steps of: applying row drive signals to said row electrodes, respectively; and applying one of first, second and third column drive signals to each of said column electrodes, with said first column drive signal inducing a non-display state at all of the display elements along each column electrode, said second column drive signal inducing a non-display state at a single display element along said each column electrode and inducing a display state at the other two display elements along said each column electrode, and said third column drive signal inducing a display state at all of the display elements along said each column electrode; wherein each of said row drive signals ta
    Type: Grant
    Filed: December 3, 1979
    Date of Patent: August 14, 1984
    Assignee: Citizen Watch Company Limited
    Inventors: Akira Tsuzuki, Hiro Fujita, Shigeru Morokawa
  • Patent number: 4443062
    Abstract: In a multi-layer display device such as a liquid crystal display, each of a plurality of sets of display elements is defined by a corresponding common electrode and a plurality of segment electrodes. Segment electrodes of sets of display elements which will not be activated simultaneously are connected together, with at least one of these sets being maintained in a deactivated state by means of a special drive signal applied to the corresponding common electrode. The level of time-sharing which must be utilized for driving the various common electrodes, for a given number of external connections to the segment electrodes, can thereby be reduced, or the overall number of connections made to the display device can be substantially reduced.
    Type: Grant
    Filed: September 16, 1980
    Date of Patent: April 17, 1984
    Assignee: Citizen Watch Company Limited
    Inventors: Seigo Togashi, Akira Tsuzuki, Hiro Fujita
  • Patent number: 4264967
    Abstract: In an electronic timepiece, a system for producing a unit time signal with a high degree of frequency stability, composed of a low frequency oscillator, a high frequency oscillator of a high degree of frequency stability which is activated only during periodic short intervals, and means for producing a timebase signal which is an exact integral submultiple in frequency of the high frequency oscillator signal, by modifying the output signal from the low frequency oscillator on the basis of periodically recurring phase coincidence between the high and low frequency oscillator signals. Information on this phase variation is stored in digital form, and is utilized to correct the low frequency signal during periods when the high frequency oscillator is inactivated.
    Type: Grant
    Filed: October 16, 1979
    Date of Patent: April 28, 1981
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Hiro Fujita, Akira Tsuzuki
  • Patent number: 4244043
    Abstract: A system for performing frequency division of a high frequency signal by intermittent operation of a frequency dividing counter circuit and by a phase lock loop circuit, in which phase lock is periodically achieved with an output of the counter circuit. Phase lock loop circuit is of novel design which provides exact phase lock without cyclic variations from the reference phase.
    Type: Grant
    Filed: March 29, 1979
    Date of Patent: January 6, 1981
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Hiro Fujita, Akira Tsuzuki, Heihachiro Ebiha, Fukuo Sekiya
  • Patent number: 4241435
    Abstract: An electronic timepiece having a high frequency oscillator with a high level of frequency stability and an electronically controlled low frequency oscillator. The phase of a high frequency signal from the high frequency oscillator is compared with a signal from the low frequency oscillator, and a digital signal is produced in accordance with the phase difference. The digital signal alternately controls the frequency of the low frequency signal to be slightly greater than an exact submultiple of that of the high frequency signal and slightly less that an exact submultiple of the high frequency signal, so that with respect to a relatively long time interval the frequency of the low frequency signal is an exact submultiple of that of the high frequency signal, the low frequency signal being thereby utilizable as a timebase signal for the timepiece.
    Type: Grant
    Filed: October 3, 1979
    Date of Patent: December 23, 1980
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Hiro Fujita, Akira Tsuzuki
  • Patent number: 4110967
    Abstract: A method and system for driving a liquid crystal display device including a first display section arranged in a first predetermined manner and a second display section arranged in a second predetermined manner, in which the first display section is driven in a static display mode whereas the second display section is driven in a matrix display mode.
    Type: Grant
    Filed: August 31, 1976
    Date of Patent: September 5, 1978
    Inventor: Hiro Fujita
  • Patent number: 4024416
    Abstract: A frequency standard for an electronic timepiece comprising a low frequency oscillator and a high frequency oscillator of which the frequency is an integral multiple of a predetermined frequency of the lower frequency oscillator. A phase difference detector is coupled to the lower and higher frequency oscillators to produce a signal occurring at intervals depending on the phase difference between the two oscillators. A frequency divider is provided to divide down the frequency of the signal by the integral multiple to produce a phase difference signal. The phase difference signal is algebraically added to the lower frequency oscillator signal to generate an output signal of which frequency is equal to that of the high or frequency oscillation signal divided by the integral multiple.
    Type: Grant
    Filed: May 10, 1976
    Date of Patent: May 17, 1977
    Assignee: Citizen Watch Co., Ltd.
    Inventors: Hiro Fujita, Shigeru Morokawa, Akira Tsuzuki