Citizen Watch Company, Ltd.

Other

Fukuo Sekiya

Heihachiro Ebihara

Takashi Yamada

Shigeru Morokawa

Yasushi Nomura

Yukio Hashimoto

Keiichiro Koga

Katsuo Nishimura

Minoru Natori

Misao Uchino

Minoru Watanabe

Hiroshi Ogawa

Toshikazu Hatuse

Kouhei Kawanobe

Kazunari Kume

Takanori Nanya

Akira Tsuzuki

Ryoji Iwakura

Hiro Fujita

Yuzo Maekawa

Hiroshi Shimizu

Itsunari Hayabuchi

Akira Nakai

Heihachiro Ebiha

Ryuichi Maruka

A drive circuit for producing scanning pulses to successively select row or column conductors of a matrix display device of the type having an active element provided for each display element in the matrix, the drive circuit comprising a shift register made up of a set of cascade-connected master-slave flip-flops, with both the master outputs and the 'slave' outputs being utilized to form the scanning pulses. The number of flip-flop stages required is reduced by 1/2, by comparison with prior art drive circuits using master-slave flip-flops, and the frequency of the clock pulse signal required to drive the shift register is 1/2 of that required in the case of a prior art circuit.

Driver circuit for matrix type display device

A drive circuit for sequentially driving electrodes of a matrix display device such as a liquid crystal display panel comprises a shift register divided into a plurality of groups of shift register stages and means for selectively applying a first clock signal and a second signal to the groups of stages, so that the groups become successively operative and so that power consumption of the currently inoperative groups is minimized. The second signal can comprise a low-frequency refresh clock signal, in the case of a dynamic type of shift register, or a DC potential in the case of static-type shift registers. During changeover between adjacent groups of shift register stages, the first clock signal is applied simultaneously to both groups, in order to ensure stable operation.

Drive circuit for matrix display device

An improved drive method is disclosed for a liquid crystal matrix display panel having display elements driven by a set of common conductors which are successively addressed during row selection intervals and a set of segment conductors to which data signals are applied, whereby the number of transitions of polarity of the drive voltage applied to each display element during a non-selection interval for that display element in each frame, as measured over any four successive frame intervals, is made independent of the display pattern formed by the column of display elements containing that display element, with the polarity transitions being distributed substantially uniformly throughout each set of four frame intervals. Contrast variations which arise with prior art drive methods for large-area high element-density displays, due to pattern-dependent effects resulting from matrix conductor resistance and display element capacitance, are thereby completely eliminated.

Liquid crystal matrix display panel drive method

A row conductor drive circuit for a matrix display device, to be formed directly upon one substrate of a display panel, is divided into a number of circuit sections connected in series each comprising at least two shift registers. Only one shift register in a circuit section is made operable to produce row conductor scanning signals, the operable shift register being selected based on testing performed after manufacture and with shift registers being selectively set in the operable or non-operable states by potentials applied to control terminals provided in the circuit sections. A set of properly operating shift registers are thereby effectively connected in series to produce row conductor scanning signals even if some shift registers of the circuit sections are defective. Manufacturing yield of the display device is thereby substantially increased.

Row conductor scanning drive circuit for matrix display panel

A writable non-volatile memory circuit for use in portable electronic devices such as electronic timepiece, wherein there is improved the power consumption and there is provided a volatile memory with a serial input for writing the data into the non-volatile memory and for checking the data.

Non-volatile memory circuit for portable electronic devices

An electronic timepiece of analog display type is provided with at least one other additional function mode such as an alarm mode in addition to a current time mode of operation. When changeover from one function mode to another is performed, by actuation of an external operating member, information indicated by the timepiece analog display is rapidly changed over to correspond to information for the new function mode, e.g. is rapidly changed over to indicate an alarm time when changeover from the current time mode to the alarm time mode is performed, and rapidly changed to indicate current time when the reverse mode changeover is performed.

Analog display electronic timepiece with multi-mode display capability

In an electronic timepiece having a primary frequency divider circuit coupled to receive a standard frequency signal and comprising a group of P-channel FETs and a group of N-channel FETs, a bias circuit supplies a bias input to the P-channel FET group and a separate bias input to the N-channel FET group. By providing these bias inputs through current mirror coupling from a standard current source, the response of the primary frequency divider circuit to low amplitudes of the standard frequency signal can be made substantially independent of timepiece battery voltage variations, over a wide range of battery voltages.

Electronic timepiece having improved primary frequency divider response

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.

Electronic timepiece

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.

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.

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.

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.

An electronic timepiece having a first display unit which indicates the present time by means of digital values, and a second display unit of the hand type which displays the time set by an additional function such as alarm function by means of one or more hands.

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, timing signals, and a plurality of word pulses indicative of a plurality of data words representing time data concerning the current time and additional data concerning alarm time. A timekeeping register stores the time data and the additional data and provision is made for generating a carry signal in dependence on the time data. The information in the register is altered in response to the time unit signal and the carry signal to update the time data and provision is made to write in the additional data into the register. The coincidence between the current time and the alarm time is detected by an alarm unit which generates a coincidence signal indicative thereof. Display elements responsive to an output of the timekeeping register are operable to display the time data and the additional data.

Electronic alarm timepiece

A portable electronic device with calculation and timekeeping functions, equipped with a keyboard for calculation and time setting purposes, means for producing scanning signals when a key is actuated, these signals being applied to switching elements connected to rows of keyboard contacts. When a key is depressed, the resultant high level signal potential applied to the corresponding contact row causes the row position to be detected and stored in a first memory circuit, which produces a signal causing the corresponding contact column to be detected and stored in a second memory circuit. Actuation of an external control member causes a signal to be stored by a reset signal in a first stage memory circuit which produces an output signal to be subsequently stored in a second stage memory circuit in synchronism with a timing signal. The low frequency and low duty cycle of the scanning signals and reset signal ensure minimized power consumption and suppression of switch bounce effects.

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Tokorozawa, Japan

Fukuo Sekiya