Semiconductor display device and method of driving the same
First Claim
1. A semiconductor display device comprising:
- a source signal line drive circuit unit constituted by plural thin-film transistors;
a gate signal line drive circuit unit constituted by plural thin-film transistors; and
a pixel unit in which plural pixel thin-film transistors are arranged like a matrix;
wherein, the gate signal line drive circuit has at least one tristate buffer per a gate signal line;
the tristate buffer has;
a first circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor; and
a second circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor;
the source region of the n-channel thin-film transistor in the first circuit is electrically connected, at a first connection point, to the source region of the p-channel thin-film transistor of the second circuit;
a first power source is electrically connected to the source region of the p-channel thin-film transistor of the first circuit;
a second power source having a potential lower than that of the first power source is electrically connected to the first connection point;
a third power source having a potential lower than the second power source is electrically connected to the source region of the n-channel thin-film transistor of the second circuit; and
an output signal line of the first circuit and an output signal line of the second circuit are both electrically connected to the gate signal line at a second connection point.
1 Assignment
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Accused Products
Abstract
In executing the opposing common inverse drive in an active matrix-type semiconductor display device, a gate bias is suppressed to be comparable with that of the conventional inverse drive to avoid a range in which the off current jumps up and, hence, to suppress the leakage of the stored electric charge, thereby to maintain an ON/OFF margin of the pixel TFTs. The gate bias applied to the pixel TFT is maintained to be near the customarily employed voltage to maintain a gate breakdown voltage, and the electric power is consumed in a decreased amount by the drive circuit as a whole, thereby to provide a novel drive circuit. In the semiconductor display device, a tristate buffer is used for a gate signal line drive circuit, and different buffer potentials are applied depending upon a frame in which the opposing common potential assumes a positive sign and a frame in which the opposing common potential assumes a negative sign. thereby to maintain an ON/OFF margin of the pixel TFTs. The voltage amplitude is decreased during the opposing common inverse drive.
82 Citations
20 Claims
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1. A semiconductor display device comprising:
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a source signal line drive circuit unit constituted by plural thin-film transistors;
a gate signal line drive circuit unit constituted by plural thin-film transistors; and
a pixel unit in which plural pixel thin-film transistors are arranged like a matrix;
wherein,the gate signal line drive circuit has at least one tristate buffer per a gate signal line;
the tristate buffer has;
a first circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor; and
a second circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor;
the source region of the n-channel thin-film transistor in the first circuit is electrically connected, at a first connection point, to the source region of the p-channel thin-film transistor of the second circuit;
a first power source is electrically connected to the source region of the p-channel thin-film transistor of the first circuit;
a second power source having a potential lower than that of the first power source is electrically connected to the first connection point;
a third power source having a potential lower than the second power source is electrically connected to the source region of the n-channel thin-film transistor of the second circuit; and
an output signal line of the first circuit and an output signal line of the second circuit are both electrically connected to the gate signal line at a second connection point. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 14)
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2. A semiconductor display device comprising:
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a source signal line drive circuit unit constituted by plural thin-film transistors;
a gate signal line drive circuit unit constituted by plural thin-film transistors; and
a pixel unit in which plural pixel thin-film transistors are arranged like a matrix;
wherein,the gate signal line drive circuit has at least one tristate buffer per a gate signal line;
the tristate buffer has;
a first circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor; and
a second circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor;
the source region of the n-channel thin-film transistor in the first circuit is electrically connected, at a first connection point, to the source region of the p-channel thin-film transistor of the second circuit;
a first power source is electrically connected to the source region of the p-channel thin-film transistor of the first circuit;
a second power source having a potential lower than that of the first power source is electrically connected to the first connection point;
a third power source having a potential lower than the second power source is electrically connected to the source region of the n-channel thin-film transistor of the second circuit;
an output signal line of the first circuit and an output signal line of the second circuit are both electrically connected to the gate signal line at a second connection point;
a gate signal line selection pulse is input to the gate of the p-channel thin-film transistor of the first circuit;
a first signal is input to the gate of the n-channel thin-film transistor of the first circuit;
a second signal is input to the gate of the p-channel thin-film transistor of the second circuit;
a third signal is input to the gate of the n-channel thin-film transistor of the second circuit;
when a frame period in which the opposing electrode assumes a high potential is regarded to be a first frame period and a frame in which the opposing electrode has a low potential is regarded to be a second frame period during the opposing common inverse drive, the third signal is input during a fly-back period of when the first frame period is being changed over to the second frame period;
the second signal is input just before the gate signal line selection pulse is input; and
the first signal is input during a period of from when the gate signal line selection pulse is output in the second frame period until when the second signal is output in the first frame period, and during a period of from when the gate signal line selection pulse is output in the first frame period until when the third signal is input in the fly-back period. - View Dependent Claims (15)
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10. A semiconductor display device comprising:
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a source signal line drive circuit unit constituted by plural thin-film transistors;
a gate signal line drive circuit unit constituted by plural thin-film transistors; and
a pixel unit in which plural pixel thin-film transistors are arranged like a matrix;
wherein,the gate signal line drive circuit has at least one tristate buffer per a gate signal line;
the tristate buffer has;
a first circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor;
a second circuit that includes a pair of n-channel thin-film transistor and p-channel thin-film transistor;
a reset/set flip-flop circuit; and
a NOR circuit;
the source region of the n-channel thin-film transistor in the first circuit is electrically connected, at a first connection point, to the source region of the p-channel thin-film transistor of the second circuit;
a first power source is electrically connected to the source region of the p-channel thin-film transistor of the first circuit;
a second power source having a potential lower than that of the first power source is electrically connected to the first connection point;
a third power source having a potential lower than the second power source is electrically connected to the source region of the n-channel thin-film transistor of the second circuit;
an output signal line of the first circuit and an output signal line of the second circuit are both electrically connected to the gate signal line at a second connection point;
a gate signal line selection pulse is input to the gate of the p-channel thin-film transistor of the first circuit;
a first signal is input to the gate of the n-channel thin-film transistor of the first circuit;
a second signal is input to the gate of the p-channel thin-film transistor of the second circuit;
a third signal is input to the gate of the n-channel thin-film transistor of the second circuit;
when a frame period in which the opposing electrode assumes a high potential is regarded to be a first frame period and a frame in which the opposing electrode has a low potential is regarded to be a second frame period during the opposing common inverse drive, the third signal is input during a fly-back period of when the first frame period is being changed over to the second frame period;
the second signal is input just before the gate signal line selection pulse is input; and
the first signal is an output signal of a NOR circuit that receives the gate signal line selection pulse and a set output signal obtained by inputting a gate signal line selection pulse to the reset signal input line of the reset/set flip-flop circuit and by inputting the third signal to the set signal input line. - View Dependent Claims (11, 12, 13, 16)
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17. A semiconductor display device comprising:
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a source signal line drive circuit unit and a gate signal line drive circuit unit formed over a substrate, said gate signal line drive circuit having at least one tristate buffer per a gate signal line;
said tristate buffer comprising;
at least a first circuit and a second circuit, a first power source electrically connected to said first circuit;
a second power source having a potential lower than that of said first power source; and
and a third power source having a potential lower than that of said second power source and electrically connected to said second circuit. - View Dependent Claims (18)
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19. A method of driving a semiconductor display device having a source signal line drive circuit unit constituted by plural thin-film transistors, a gate signal line drive circuit unit constituted by plural thin-film transistors, and a pixel unit in which plural pixel thin-film transistors are arranged like a matrix, said method comprises:
wherein pixel TFTs constituting an active matrix circuit are driven by using three kinds of potentials which are a first power-source potential, a second power-source potential and a third power-source potential. - View Dependent Claims (20)
Specification