Driving circuit, electro-optical device, method of driving the same, and electronic apparatus
View Patent ↗When respective bits of grayscale data Dx 1 are ‘0’ which represents black, upon detection, a NOR circuit of a voltage supply circuit sets an output signal active. Then, a transistor is turned on, and a black voltage VBr is supplied to a data line. By this embodiment, since all transistors of a current supply circuit are turned off, a current is not outputted. Meanwhile, in the case in which a grayscale level to be displayed is other than black, a current Idata is outputted from the current supply circuit.
1. A driving circuit for an electro-optical device including a plurality of scanning lines, a plurality of data lines, and a plurality of pixel circuits respectively provided at intersections of the scanning lines and the data lines, each of the pixel circuits including a self-luminous element, and a current storing element for supplying current supplied via a data line, the stored current being supplied to the self-luminous element according to a signal supplied to each of the scanning lines, the driving circuit comprising:
voltage supply means for, when a grayscale level to be displayed is a predetermined grayscale level, outputting a predetermined voltage to each of the data lines;
current supply means for, when the grayscale level to be displayed is not the predetermined grayscale level, outputting a current according to the grayscale level to each of the data lines, and the current supply means Setting an output terminal to a high impedance state when the grayscale level to be displayed is the predetermined grayscale level;
control means for, when the grayscale level to be displayed is the predetermined grayscale level, activating the voltage supply means to supply the predetermined voltage and deactivating a current supply from the current supply means, and for, when grayscale level to be displayed is not the predetermined grayscale level, deactivating the voltage supply means and activating the current supply means,
the control means connecting the voltage supply means to the data line, during a first period of a writing period in which the data lines are selected, the control means connecting the current supply means to the data line during a second period of the writing period,
the voltage supply means writing the predetermined voltage into the data line during the first period of the writing period in which the data lines are selected and when the grayscale level to be displayed is the predetermined grayscale level, the voltage supply means writing a precharge voltage into the data line when the grayscale level to be displayed is not the predetermined grayscale level, and
the current supply means during the second period of the writing period in which the data lines are selected, setting the data lines to a high impedance state when a grayscale level to be displayed is a predetermined grayscale level, and supplying a current depending on the grayscale level to be displayed to each of the data lines when the grayscale level to be displayed is not the predetermined grayscale level.
2. The driving circuit according to claim 1 , wherein each of the pixel circuits comprises a driving transistor serving as a current source of the self-luminous element, a capacitive element provided between a gate and a source of the driving transistor, and means for storing charges in the capacitive element such that a gate-source voltage of the driving transistor depends on the current supplied via each of the data lines, and wherein the voltage supply means generates, as the predetermined voltage, a voltage that turns off the driving transistor.
3. The driving circuit according to claim 2 , further comprising: power supply means for generating a power supply voltage and for supplying the power supply voltage to a source of the driving transistor of each of the pixel circuits, wherein the voltage supply means comprises voltage control means for controlling the predetermined voltage depending on the power supply voltage and generates the predetermined voltage such that the driving transistor is turned off.
4. The driving circuit according to claim 1 , wherein the predetermined grayscale level to be displayed is black.
5. An electro-optical device comprising: a plurality of scanning lines; a plurality of data lines; a plurality of pixel circuits respectively provided at intersections of the scanning lines and the data lines, each pixel circuit having a self-luminous element, a driving transistor serving as a current source of the self-luminous element, a capacitive element provided between a gate and a source of the driving transistor, and means for storing charges in the capacitive element such that a gate-source voltage of the driving transistor depends on a current supplied via the data lines; and a driving circuit as claimed in claim 1 .
6. The electro-optical device according to claim 5 , wherein the self-luminous element is an organic light emitting diode.
7. An electronic apparatus comprising an electro-optical device as claimed in claim 6 .
8. A method of driving an electro-optical device including a plurality of scanning lines, a plurality of data lines, and a plurality of pixel circuits respectively provided at intersections of the scanning lines and the data lines, in which each of the pixel circuits includes a self-luminous element, and stores a current supplied via each of the data lines, and supplies the stored current to the self-luminous element according to a signal supplied via each of the scanning lines, the method comprising the steps of:
generating a predetermined voltage when a grayscale level to be displayed is a predetermined grayscale level and generating a precharge voltage when a grayscale level to be displayed is not the predetermined grayscale level;
generating a current depending on grayscale level when the grayscale level to be displayed is not the predetermined grayscale level, and generating a current and setting an output terminal to a high impedance state when the grayscale level to be displayed is the predetermined grayscale level;
supplying the predetermined voltage to each of the data lines when the grayscal'e level to be displayed is the predetermined grayscale level; and
supplying the current depending on the grayscale level to be displayed to each of the data lines when the grayscale level to be displayed is not the predetermined grayscale level,
supplying a voltage to the data line during a first period of a writing period in which the data lines are selected, and supplying the current to the data line during a second period of the writing period,
writing the predetermined voltage into the data line during the first period of the writing period in which the data lines are selected, when the grayscale level to be displayed is the predetermined grayscale level and, writing a precharge voltage into the data line when the grayscale level to be displayed is not the predetermined grayscale level, and
during the second period of the writing period in which the data lines are selected, setting the data lines to a high impedance state when a grayscale level to be displayed is a predetermined grayscale level, and supplying a current depending on the grayscale level to be displayed to each of the data lines when the grayscale level to be displayed is not the predetermined grayscale level.
9. The method of driving an electro-optical device according to claim 8 , wherein each of the pixel circuits comprises a driving transistor serving as a current source of the self-luminous element, a capacitive element provided between a gate and a source of the driving transistor, and means for storing charges in the capacitive element such that a gate-source voltage of the driving transistor depends on the current supplied via each of the data lines, and wherein the predetermined voltage is a voltage that turns off the driving transistor.
10. The method of driving an electro-optical device according to claim 9 , further comprising the steps of generating a power supply voltage to be supplied to a source of the driving transistor of each of the pixel circuits; and controlling the predetermined voltage depending on the power supply voltage such that the driving transistor is turned off.
11. The method of driving an electro-optical device according to claim 7 , wherein the predetermined grayscale level to be displayed is black.
12. The method of driving an electro-optical device according to claim 8 , wherein the self-luminous element is an organic light emitting diode.