Expansion system for a liquid crystal display

• US 4,662,718 A
• Filed: 10/19/1984
• Issued: 05/05/1987
• Est. Priority Date: 10/20/1983
• Status: Expired due to Fees

• Current Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Masubuchi, Sadao
• Primary Examiner(s): Evans, Arthur G.
• Application Number:
  US06/662,688
• Time in Patent Office: 928 Days
• Field of Search: 350/332, 350/333, 340/800, 340/801, 340/814, 340/784, 340/707, 340/765
• US Class Current: 345/99
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: H04N 3/127 using liquid crystals

Abstract

An expansion system for a liquid crystal video display device having a plurality of scanning electrodes, a plurality of data electrodes, drivers for respectively driving the scanning electrodes and data electrodes. The scanning electrodes and data electrodes are driven only during an expansion period in a field, and voltage between the scanning electrode and the data electrode is zero during a non-expansion period in the field.

Claims

1. An improved expansion system for a liquid crystal video display device of the type having a plurality of scanning electrodes, a plurality of data electrodes, drivers for respectively driving the scanning electrodes and data electrodes, a separator for separating a video signal into a horizontal sync signal and a vertical sync signal, a control unit for controlling the drivers in accordance with the sync signals, wherein the improvement comprises:

means for applying signals to the drivers during an expansion period in a field so as to apply drive voltages to the scanning electrodes and data electrodes, and for applying approximately equal voltages to scanning electrodes and data electrodes causing the voltage between scanning electrodes and data electrodes to go to zero or about zero during the non-expansion period in the field.

2. An improved expansion system for a liquid crystal video display device of the type having a plurality of scanning electrodes, a plurality of data electrodes, drivers for respectively driving the scanning electrodes and data electrodes, a separator for separating a video signal into a horizontal sync signal and a vertical sync signal, a control unit for controlling the drivers in accordance with the sync signals, wherein the improvement comprises:

means included in said control unit for applying signals to the drivers during an expansion period in a field so as to apply drive voltages to the scanning electrodes and data electrodes, and for applying approximately equal voltages to scanning electrodes and data electrodes causing the voltage between scanning electrodes and data electrodes to go to zero or about zero during the non-expansion period in the field, said means comprising counters responsive to the horizontal and vertical sync signals for producing signals during the expansion period, start pulse generators responsive to the signals from the counters for starting the drivers operating to drive the scanning and data electrodes, and shift pulse generators responsive to the signal from the counters for shifting the operations of the drivers and for performing the horizontal scanning and vertical scanning.