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US 4,393,379 AGranted
Non-multiplexed LCD drive circuit
OwnerJohn P. Berting, James K. Kroegerinventors
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OwnerJohn P. Berting, James K. Kroegerinventors
Estimating the term…
A liquid crystal display circuit (9) comprises a recirculating shift register (14) having serial input and output terminals for receiving and generating binary data in bit serial format and a plurality of intermediate parallel output terminals for coupling display data to a liquid crystal display (LCD) (10). Display data are loaded into the shift register (14) during a display update mode and recirculated for display by the LCD (10) during a data refresh mode. Loading and recirculation of display data are controlled by logic circuitry (16) in a feedback loop (15, 17) of the recirculating shift register (14). To minimize DC buildup on the LCD (10), data inversion provided in the feedback loop causes periodic polarity reversal of data during recirculation. In addition, a shift register reset circuit (28) monitors the continuity of data being supplied to the LCD (10) for display. The reset circuit (28) resets the shift register (14) in response to discontinuities in input data flow to further minimize DC buildup.
A liquid crystal display (LCD) drive circuit using recirculating shift register means for generating bit parallel output data to be applied to an LCD for display as a stationary image by repetitively recirculating a number of bits corresponding to a number of stages of said register means and, upon completion of each recirculation of bits, transferring the contents of said register means to said LCD, the drive circuit comprising display update means for loading display data into said shift register means, display refresh means including data inversion means for recirculating data stored in said shift register means, switch means for selectively operating said update and refresh means, clock means for shifting data stored in said shift register means and means synchronized to the clock means for transferring the bit parallel data from said shift register to be displayed as a stationary image on said LCD.
A liquid crystal display (LCD) drive circuit using a recirculating shift register having a serial input terminal, a serial output terminal and a plurality of intermediate, parallel output terminals, said parallel output terminals being coupled to an LCD, said shift register means being controlled by said drive circuit to repetitively recirculate a number of bits corresponding to a number of stages of said register means and, upon completion of each recirculation of bits, transferring the contents of said register means to said LCD, the drive circuit comprising switch means for selectively (1) updating said LCD by applying display data to said serial input terminal to load said shift register and (2) refreshing said LCD by coupling together said input and output terminals of said shift register for recirculation and inversion of loaded data;
A liquid crystal display (LCD) circuit comprising an LCD for visually displaying data applied thereto;
The circuit of claim 6, wherein said shift register means includes a CLEAR terminal, and said clearing means includes an R-C circuit coupled to said CLEAR terminal and to a source of input data.
Dependencies are inferred from the claim text.