Patent ID: 6961053

Claim:
A passive matrix type LCD display device capable of controlling the density of a visual presentation given in the form of a combination of selected segments, the display device comprising: an LCD display comprising a predetermined segment arrangement having a plurality of common terminals connected to its individual segments and a similar counter segment arrangement having a plurality of segment terminals connected to its counter segment; a two or more time-division dynamic LCD drive; and a dormancy determining controller; wherein the dormancy determining controller supplies a controlled number M of AC drive voltage waves, M being an integer, each AC drive voltage wave having a period T, to add to a series of AC drive voltage waves each having a period T supplied from the two or more time-division dynamic LCD drive, the AC drive voltage waves being applied sequentially in time-division to all common terminals of the LCD display, the controlled number M varying to provide on the LCD display an image whose unclearness is reduced; and wherein the dormancy determining controller selects within a single frame period at least one predetermined dormant period T 0 during which the resulting voltage difference between all the common and segment terminals is zero.