USA As Represented by Secretary of the Navy

Geo-centers, Inc.

Anno Hermanns

Geoffrey Louis Barrows

Banhalli R Ratna

An active matrix circuit for compact, high resolution reflective liquid ctal displays includes a low quiescent current, low output impedance MOS transistor amplifier produced in a CMOS process. A voltage controlled input switch effects the voltage refresh of the active matrix cell by passing a data voltage to the input of the transistor amplifier when a control voltage pulse is present on the input switch control line. All active matrix cells in a given row use the same input switch control line, and all active matrix cells in a given column access the same data input line. Refresh of the active matrix cell voltage terminates when the input switch is opened, storing the data voltage on the input node capacitance of the amplifier. The active matrix circuit is particularly addressed to liquid crystal devices having fast, analog response liquid crystals with large molecular polarizations such as in the Electroclinic Liquid Crystals (ELC). Including such an amplifier in each active matrix cell facilitates delivery of the large charge required to switch such liquid crystals without incurring a concomitant drop in pixel voltage, as encountered with other active matrix cell circuits.

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Fort Belvoir, VA, United States of America

Anno Hermanns