DISPLAY, METHOD, AND 5T1C N-TYPE PIXEL CIRCUIT
Active Matrix Organic Light-Emitting Diode (AMOLED) displays, novel pixel circuits therefore, and methods of programming and driving the pixel circuit are disclosed. A pixel circuit includes five TFT transistors, a light-emitting device and a storage capacitor coupled to an external voltage supplied through a voltage line and is driven using a plurality of operation states effecting in-pixel compensation.
1 . A display system comprising:
an array of pixel circuits arranged in rows and columns, a pixel circuit of the array of pixel circuits including:
a drive transistor coupled between a first and a second supply voltage and including a source terminal coupleable to a data line of the display system;
a storage capacitor coupled across a gate terminal of the drive transistor and a voltage line;
a light-emitting device coupled between the first supply voltage and the source terminal of the drive transistor, and
a controller for driving the pixel circuit in a drive mode including a plurality of operation states for the pixel circuit including a programming and in-pixel compensation state at least for programming the storage capacitor of the pixel circuit with use of a data voltage provided over the data line.
2 . The display system of claim 1 , wherein the voltage line is kept at a constant voltage level.
3 . The display system of claim 2 , wherein the constant voltage level is a voltage level different from voltage levels of the first and the second supply voltages.
4 . The display system of claim 2 , further comprising an initialization transistor coupled across a drain terminal and the gate terminal of the drive transistor.
5 . The display system of claim 4 , wherein the initialization transistor is for coupling the gate and drain terminals of the drive transistor during an initialization state.
6 . The display system of claim 5 , wherein the initialization transistor is for coupling the gate and drain terminals of the drive transistor during a programming and in-pixel compensation state, wherein the drive transistor discharges a gate voltage of the gate terminal until the drive transistor turns off.
7 . The display system of claim 6 , further comprising a first emission transistor coupled between the first supply voltage and the drain terminal of the drive transistor and a second emission transistor coupled between the source terminal of the drive transistor and the second supply voltage, the first and second emission transistors for allowing current to pass between the first and second supply voltages and though the light-emitting device during an emission state.
8 . The display system of claim 7 , further comprising a write transistor coupled between the source terminal of the drive transistor and the data line, for said programming the storage capacitor with use of the data voltage during the programming and in-pixel compensation state.
9 . The display system of claim 8 , wherein the pixel circuit comprises transistors which are only N-type TFTs, and wherein said light-emitting device is an organic light-emitting diode (OLED) device.
10 . A method of driving a display system, the display system including an array of pixel circuits arranged in rows and columns, a pixel circuit of the array of pixel circuits including: a drive transistor coupled between a first and a second supply voltage and including a source terminal coupleable to a data line of the display system; a storage capacitor coupled across a gate terminal of the drive transistor and a voltage line; and a light-emitting device coupled between the first supply voltage and the source terminal of the drive transistor, the method comprising:
driving the pixel circuit in a plurality of operation states for the pixel circuit including:
during a programming and in-pixel compensation state, programming the storage capacitor of the pixel circuit with use of a data voltage provided over the data line.
11 . The method of claim 10 , wherein during the plurality of operation states the voltage line is kept at a constant voltage level.
12 . The method of claim 11 , wherein the constant voltage level is kept at a voltage level different from voltage levels of the first and the second supply voltages.
13 . The method of claim 12 , wherein the display system includes an initialization transistor coupled across a drain terminal and the gate terminal of the drive transistor, and driving the pixel circuit in the plurality of operation states further comprises:
during an initialization state, coupling the gate and drain terminals of the drive transistor with the initialization transistor.
14 . The method of claim 13 , wherein driving the pixel circuit in the plurality of operation states further comprises:
during the programming and in-pixel compensation state, using the initialization transistor to couple the gate and drain terminals of the drive transistor allowing the drive transistor to discharge a gate voltage of the gate terminal until the drive transistor turns off.
15 . The method of claim 14 , wherein the display system includes a first emission transistor coupled between the first supply voltage and the drain terminal of the drive transistor and a second emission transistor coupled between the source terminal of the drive transistor and the second supply voltage, and wherein driving the pixel circuit in the plurality of operation states further comprises:
during an emission state turning the first and second emission transistors on to allow current to pass between the first and second supply voltages and though the light-emitting device.
16 . The method of claim 15 , wherein the display system includes a write transistor coupled between the source terminal of the drive transistor and the data line, and wherein driving the pixel circuit in the plurality of operation states further comprises:
during the programming and in-pixel compensation state, using the write transistor to program the storage capacitor with use of the data voltage.
17 . The method of claim 16 , wherein the pixel circuit comprises transistors which are only N-type TFTs, and wherein said light-emitting device is an OLED device.