16-08-1978 дата публикации
Номер: GB1521814A
Автор:
1521814 Electronic timepieces TIMEX CORP 10 May 1976 [2 Sept 1975] 19199/76 Heading G3T [Also in Division G5] In an electrochromic display cell 8, e.g. in a figureof-eight array in an electronic timepiece, simultaneous fade-in and fade-out without the ambiguities of 'erase before write' and vice-versa is provided by a squarewave drive voltage Ï, alternating between two levels, supplied to a counter electrode 10 common to all segments, the segment electrodes of those to be written being connected to the opposite level only during the 'write' half cycle, while the segment electrodes of those to be erased are connected to the level opposite to the supply only during the 'erase' half-cycle. In their inactive half-cycles the segment electrode potentials float, leaving the 'write' electrodes at a mean negative voltage and the 'erase' electrodes at a mean positive voltage relative to the counter electrodes. The frequency is chosen so that only a fraction of the write or erase process takes place in one cycle, giving apparent smooth fade-in and fade-out. Each segment electrode is connected to the write (low) and erase (high) levels by switches 12, 14, closed by AND gates 16, 17 when the respective supply wave 0 or its inverse # is high and a command high signal is received on inputs 19, 21. In a timepiece circuit, Figs. 4, 5 (not shown), a decoder is provided for each segment of the arrays, driven by hours, minutes, month and date counters, providing logic signals to 'write' and 'erase' AND gates of those segments to be changed, via a flip-flop memory. A 'refresh' input is provided for maintaining contrast by occasional pulses, and to by-pass the flip-flop during manual adjustment.
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