A watch having a liquid crystal display for the digital display of time in response to timing signals produced by divider and driving circuits, which in turn produce said timing signals in response to the high frequency time standard signal of a quartz crystal oscillator. A switch means is coupled to said driving circuits for rendering said liquid crystal display inoperative without disturbing said oscillator and divider circuit.
A driving system for liquid crystal display devices comprises a plurality of sets of liquid crystal display devices. Each set includes a liquid crystal whose state changes visually at a visual threshold voltage and first and second electrodes which serve to apply potential differences to the liquid crystal. Potentials of a high level, a low level and a medium level are selectively applied to the respective first electrodes, and the potentials of the high level and the low level are selectively applied to the respective second electrodes. The potential difference between the high level potential to be applied to the first electrodes and the low level potential to be applied to the second electrode, and the potential difference between the low level potential to be applied to the first electrodes and the high level potential to be applied to the second electrodes have values larger than the visual threshold voltage. The potential difference between the medium level potential to be applied to the first electrodes and the high or low level potential to be applied to the second electrodes has a value smaller than the visual threshold voltage.
The invention relates to a circuit array for operating a liquid-crystal display in the time-division multiplexing mode, the display having at least one backplane and several segments. The circuit array includes a microprocessor having a first pulse generator, a shift register array storing data signals supplied to the circuit array, this shift register array having a number of stages corresponding to the number of segments, and driving stages which generate segment pulse sequences for the segments in accordance with the supplied data signals. In accordance with the invention, the microprocessor supplies the data signals to the shift register array via a first interface, the shift register array being designed as a cyclic shift register with each register point of the shift register array being clearly allocated to a segment. In addition, the microprocessor supplies control data, particularly data determining the time multiplexing rate, to a second interface having a decoder. The decoded control data is passed to a pulse generator that generates a pulse sequence corresponding to a backplane pulse sequence, excepting the voltage level. Finally, each driving stage is supplied with a pulse sequence in order to generate the segment pulse sequences corresponding to the contents of the register points of the cyclic shift register.
A driving system for a liquid crystal display device includes a first and common electrode, a plurality of second electrodes, and a liquid crystal interposed between the first and second electrodes and has a visual threshold voltage at which the state of the liquid crystal changes visually. A potential difference not smaller than the visual threshold voltage is applied between the first electrode and a selected one or more of the second electrodes. A medium potential between potentials applied to the first electrode and to the selected second electrode or electrodes is applied to the second electrodes which are not selected. The potential difference between the medium potential and the potential applied to the first electrode is smaller than the visual threshold voltage.
