Matrix panel with an active driving system
First Claim
1. An active driving system for a liquid crystal matrix panel, having a plurality of cells each including a transistor for switching the cell on and off during selected and non-selected periods respectively and a picture element, said matrix panel receiving an external video signal adapted to a cathode ray tube display and a frame signal, the active driving system comprising:
- inverter means for inverting the polarity of the external video signal;
scaling means coupled to the inverter means for symmetrically amplifying the inverted video signal to produce two negative-video signals having bias voltages and amplitudes which are symmetrical to a common voltage level; and
selector means coupled to the scaling means for producing a composite negative-video signal by alternating selecting the two negative-video signals.
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Accused Products
Abstract
In the matrix, a positive type liquid crystal of the twisted nematic type is driven by a thin film transistor arranged on a transparent substrate. The polarity of the video signal, originally generated for a cathode ray tube, is inverted within a driving circuit and the inverted negative video signal is used to drive the positive type liquid crystal display. In the range of voltages of the video signal which correspond to the white level, the active matrix panel is driven by stretching the voltage of the video signal such that comparable voltage-contrast characteristics are achieved with the liquid crystal display as with the cathode ray tube. Leakage current of the thin film transistor during off-periods is reduced by setting a gate voltage during the off-period which is within the range of voltage level of the power source.
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Citations
19 Claims
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1. An active driving system for a liquid crystal matrix panel, having a plurality of cells each including a transistor for switching the cell on and off during selected and non-selected periods respectively and a picture element, said matrix panel receiving an external video signal adapted to a cathode ray tube display and a frame signal, the active driving system comprising:
- inverter means for inverting the polarity of the external video signal;
scaling means coupled to the inverter means for symmetrically amplifying the inverted video signal to produce two negative-video signals having bias voltages and amplitudes which are symmetrical to a common voltage level; and
selector means coupled to the scaling means for producing a composite negative-video signal by alternating selecting the two negative-video signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- inverter means for inverting the polarity of the external video signal;
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14. An active driving system for a liquid crystal matrix panel, having a plurality of cells each including a transistor for switching the cell on and off during selected and non-selected periods, respectively and a picture element, said matrix panel receiving an external video signal adapted to a cathode ray tube display and a frame signal, the active driving system comprising:
- inverter means for inverting the polarity of the external video signal;
scaling means coupled to the inverter means for amplifying the inverted video signal to produce two negative-video signals having amplitudes, which are symmetrical with respect to a common voltage level, and first and second bias voltages which have opposite voltage polarities; and
selector means coupled to the scaling means for producing a composite negative-video signal by alternately selecting the two negative-video signals. - View Dependent Claims (15, 16, 17, 18, 19)
- inverter means for inverting the polarity of the external video signal;
Specification