Digital watch with liquid crystal and light emitting diode displays
AssigneeHughes Aircraft Company
InventorErnest C. Ho
Life of this patent
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Abstract
A digital watch system with a dual display demultiplexer, a liquid crystal display for use in daylight or bright light and a light emitting diode display for use in dim light. The digital watch system includes a crystal oscillator with frequency division which controls a set of counters, each counter carrying coded horological data. Selected counter data is multiplexed into a seven segment decoder which is then demultiplexed into memories, one for each of the segments in each of the liquid crystal display digits. These memories then control segment drivers for the liquid crystal digital displays. In parallel with the liquid crystal demultipliexer, the seven segment decoder outputs operate segment and digit drivers which drive light emitting diodes as a second display for the digital watch.
Claims7
A digital watch for displaying selectable horological information comprising:
- first and second optical displays;
- an electronic circuit for providing information to be selectively displayed on said displays, said electronic circuit comprising an oscillator, a frequency divider coupled to the output of said oscillator for producing a timing signal, and counters for receiving said timing signal and maintaining a plurality of sets of horological information;
- a first and second control connected between said counters and said displays;
- means for causing said first display to continuously display a first set of horological information when said first and second controls are unactivated and to display a second set of horological information on said first display when said first control is activated, also said means causes said second display to display said first set of horological information when said first and second controls are simultaneously activated.
Dependencies are inferred from the claim text.