| 摘要 |
An electroscopic fluid picture-display device suitable for display television images and operating with pulse duration modulation. A picture signal sample-and-hold circuit (S/H) is followed by a pulse duration modulator (UG, DE) which comprises a first electrode (E1), a second electrode (E2) and an interposed, movable third electrode (E3) of display elements (DE) of the device (EFD, UG). The second electrode of each element is coupled to a corresponding picture voltage sampling output. The third electrode, which is interconnected with all elements, receives from a control voltage generator (UG) a control voltage (SE3) which varies over the television field period and includes a reset pulse for resetting the third to the second electrode and thereafter has a linearly decreasing control voltage. The first electrode, which is common to all elements, is thereby supplied during the field period with a constant control voltage (SE1). Both control voltages have the same polarity and the pulse voltage is approximately equal to the constant voltage. Periodically, at least once per field period, the polarity of at least the control voltages (SE1, SE3) is reversed. These control voltages may during the field period be alternating or direct voltages. The result of the given voltage supply is that the supplied television picture signal (PS) with an inherent direct voltage component does not impair the fluid (F) and hence does not interfere with the picture display with electrolysis or with charge accumulation involving electrical charging and discharging effects.
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