Display device
View Patent ↗The present invention provides a display device which includes a common electrode drive circuit having the single channel constitution which can miniaturize a circuit scale without increasing elements compared to a conventional display device. A display device includes a plurality of pixels and a common electrode drive circuit. The common electrode drive circuit includes a plurality of basic circuits, wherein the basic circuit includes a first circuit which latches a first input signal at a point of time that a clock signal is changed to a first voltage level from a second voltage level; a second circuit which latches a second input signal at the point of time that the clock signal is changed to the first voltage level from the second voltage level; a first switching circuit which is turned on based on the first circuit; and a second switching circuit which is turned on based on the the second circuit.
1. A display device comprises:
a plurality of pixels; and
a common electrode drive circuit, the common electrode drive circuit including k (k≧2) pieces of basic circuits, wherein
the n (1≦n≦k)th basic circuit comprising:
a first transistor which has a first electrode to which a first input signal is applied and a control electrode to which a (n−1)th scanning line selection signal is applied;
a second transistor which has a first electrode to which a second input signal is applied and a control electrode which is connected to the control electrode of the first transistor;
a third transistor which has a control electrode which is connected to a second electrode of the first transistor, a first electrode which is connected to an output terminal, and a second electrode to which a first power source voltage is applied;
a fourth transistor which has a control electrode which is connected to a second electrode of the second transistor, a second electrode which is connected to the output terminal, and a first electrode to which a second power source voltage is applied;
a fifth transistor which has a control electrode which is connected to the second electrode of the first transistor, and a first electrode to which the nth scanning line selection signal is applied;
a sixth transistor which has a control electrode which is connected to the second electrode of the second transistor, and a first electrode to which the nth scanning line selection signal is applied;
a first capacitive element which is connected between the second electrode of the first transistor and a second electrode of the fifth transistor;
a second capacitive element which is connected between the second electrode of the second transistor and a second electrode of the sixth transistor;
a seventh transistor which has a control electrode which is connected to the control electrode of the first transistor, a first electrode which is connected to a reference power source line to which a reference potential is supplied, and a second electrode which is connected to a second electrode of the fifth transistor; and
an eighth transistor which has a control electrode which is connected to the control electrode of the first transistor, a first electrode which is connected to the reference power source line, and a second electrode which is connected to a second electrode of the sixth transistor; wherein
after the (n−1)th scanning line selection signal is changed to a second voltage level at which the first and second transistors are turned on from a first voltage level and, at the same time, before the (n−1)th scanning line selection signal returns to the first voltage level from the second voltage level, one input signal out of the first input signal and the second input signal is changed to the second voltage level from the first voltage level,
after an nth scanning line selection signal is changed to the second voltage level from the first voltage level and, at the same time, before the nth scanning line selection signal returns to the first voltage level from the second voltage level, one input signal or another input signal out of the first input signal and the second input signal is changed to the second voltage level from the first voltage level, and
when the first input signal is at the second voltage level, the second input signal assumes the first voltage level and when the second input signal is at the second voltage level, the first input signal assumes the first voltage level.
2. A display device according to claim 1 , wherein the nth basic circuit includes:
a third capacitive element which is connected between the second electrode of the fifth transistor and the reference power source line; and
a fourth capacitive element which is connected between the second electrode of the sixth transistor and the reference power source line.
3. A display device according to claim 1 , wherein the nth basic circuit includes:
an eleventh transistor which is connected between the second electrode of the first transistor and the control electrode of the third transistor; and
a twelfth transistor which is connected between the second electrode of the second transistor and the control electrode of the fourth transistor; wherein
a given potential is applied to control electrodes of the eleventh and twelfth transistors.
4. A display device according to claim 1 , wherein the common electrode drive circuit is configured such that one basic circuit out of the odd-numbered and the even-numbered basic circuits is formed of the nth basic circuit, and another basic circuit out of the odd-numbered and the even-numbered basic circuits is formed of the nth basic circuit in which the relationship between the first input signal and the second input signal is exchanged or the relationship between the first power source voltage and the second power source voltage is exchanged.
5. A display device comprising:
a plurality of pixels; and
a common electrode drive circuit, the common electrode drive circuit including k (k≧2) pieces of basic circuits, wherein
the n (1≦n≦k)th basic circuit comprises:
a first transistor which has a first electrode to which a first input signal is applied and a control electrode to which a (n−1)th scanning line selection signal is applied;
a second transistor which has a first electrode to which a second input signal is applied and a control electrode which is connected to the control electrode of the first transistor;
a third transistor which has a control electrode which is connected to a second electrode of the first transistor, a first electrode which is connected to an output terminal, and a second electrode to which a first power source voltage is applied;
a fourth transistor which has a control electrode which is connected to a second electrode of the second transistor, a second electrode which is connected to the output terminal, and a first electrode to which a second power source voltage is applied;
a fifth transistor which has a control electrode which is connected to the second electrode of the first transistor, and a first electrode to which an nth scanning line selection signal is applied;
a first capacitive element which is connected between the second electrode of the first transistor and a second electrode of the fifth transistor; and
a sixth transistor which has a control electrode which is connected to the control electrode of the first transistor, a first electrode which is connected to a reference power source line to which a reference potential is supplied, and a second electrode which is connected to the second electrode of the fifth transistor; wherein
after the (n−1)th scanning line selection signal is changed to a second voltage level at which the first and second transistors are turned on from a first voltage level and, at the same time, before the (n−1)th scanning line selection signal returns to the first voltage level from the second voltage level, one input signal out of the first input signal and the second input signal is changed to the second voltage level from the first voltage level,
after the nth scanning line selection signal is changed to the second voltage level from the first voltage level and, at the same time, before the nth scanning line selection signal returns to the first voltage level from the second voltage level, one input signal or another input signal out of the first input signal and the second input signal is changed to the second voltage level from the first voltage level, and
when the first input signal is at the second voltage level, the second input signal assumes the first voltage level and when the second input signal is at the second voltage level, the first input signal assumes the first voltage level.
6. A display device according to claim 5 , wherein the nth basic circuit includes a third capacitive element which is connected between a second electrode of the fifth transistor and the reference power source line.
7. A display device according to claim 5 , wherein the nth basic circuit includes a ninth transistor which is connected between the second electrode of the first transistor and the control electrode of the third transistor, and
a given potential is applied to a control electrode of the ninth transistor.
8. A display device according to claim 5 , wherein the common electrode drive circuit is configured such that one basic circuit out of the odd-numbered and the even-numbered basic circuits is formed of the nth basic circuit, and another basic circuit out of the odd-numbered and the even-numbered basic circuits is formed of the nth basic circuit in which the relationship between the first input signal and the second input signal is exchanged or the relationship between the first power source voltage and the second power source voltage is exchanged.
9. A display device according to claim 1 , wherein the nth scanning line selection signal is applied to the first electrode of the fifth transistor through a diode element.