Disclosed is a solid state watch which requires no moving parts for timekeeping and display. The watch comprises a crystal controlled oscillator connected through an integrated circuit binary frequency divider to an electro-optical display in the form of light emitting diodes. The display is energized only on demand and the level of the light output is controlled in accordance with ambient light conditions. The watch is energized from a rechargeable battery.
The invention provides an advance alarm means incorporated with an electronic watch driven by a battery and fitted with a digital time display means. There is provided a detector sensing an abrupt voltage drop at the source battery. A selector represents its two states corresponding to the normal operating condition of the battery and to the voltage dropped condition thereof, respectively. This selector controls the feed of two different signal series to at least one electrically illuminatable elements of the digital time display means, depending upon the state of the selector and for providing an advance alarm before occurrence of an unacceptable voltage drop in the source battery.
An electronic watch is provided with means for digitally displaying time and date and day of the week by means of liquid crystal display elements. The display provides an indication of the second, minute and hour as well as an indication of whether it is morning or afternoon. The calendar display includes a plurality of liquid crystal display elements arranged in matrix form having seven columns each representing a day of the week and five rows each representing the weeks of the month. A plate having the days and dates of the month to be displayed is mounted on said liquid crystal element matrix by suitable means.
An electronic watch including an electronic divider for dividing the high frequency output signal of a standard oscillator into low frequency timing signals. The oscillator and divider are driven by a battery having a capacitor fixedly connected in parallel therewith to serve as a voltage source during temporary disconnection of the battery.
A time indication setting circuit for accelerating or stopping the advance of the time indicating mechanism in an electronic timepiece. A delay circuit receives time pulses developed within the timepiece and the time pulses and delayed time pulses from the delay circuit are applied to a gate circuit. The gate circuit applies the time pulses and the delayed time pulses, under the control of a control circuit, to the timepiece drive train to drive the timepiece time indicating mechanism at a rate determined by the pulse repetition rate of the pulses applied to the drive train. The control circuit is manually operable to apply the control signal so the gate circuit applies both the time and the delayed time pulses to the drive train and thereby accelerates the advance of the time indicating mechanism, or to block both the time and the time indicating pulses and thereby stop the advance of the time indicating mechanism or to apply only the time pulses to the drive train so that the time indicating mechanism advances at a normal rate.
A battery-powered quartz crystal timepiece is provided with a battery voltage detecting circuit utilizing the threshold voltage of a field effect transistor as a battery failure indicator. The voltage level at which failure is indicated may be selectively controlled by adjusting a load resistance value of the field effect transistor or a voltage divider intermediate the transistor and battery. The battery voltage detecting circuit may operate intermittently, the sampled output of the detecting circuit being stored in a memory circuit.
