The present disclosure relates to the field of display technology, and particularly to a shift register unit, a gate driving circuit and a display device
Gate drive on array (GOA) technology is a technology that replaces a driving circuit made of an external silicon wafer by directly fabricating a gate driving circuit on an array substrate. The technology can be directly achieved around a display panel, thereby reducing the manufacturing procedures, reducing the cost of product and improving the integration level of the display panel.
In a display panel based on the GOA technology, a pixel circuit that drives each pixel usually needs some external signals to control the display of the pixel. A commonly used pixel circuit shown in
The pixel circuit shown in
However, the commonly used circuits such as shift register, which generate shift signals between rows of the array substrate, are usually complicated in structure. To manufacture such a circuit around the display panel would complicate the manufacturing process of the display panel and increase the cost of the display panel.
Embodiments of the present disclosure disclose a shift register unit, a gate driving circuit and a display device, which may at least alleviate or eliminate one or more of the above problems in the prior art.
A shift register unit provided by embodiments of the present disclosure comprises two reset-set RS flip-flop. A set S terminal of a first RS flip-flop receives a trigger signal, and a reset R terminal of the first RS flip-flop receives a clock signal. An S terminal of a second RS flip-flop receives the clock signal, and an R terminal of the second RS flip-flop is connected to a Q terminal of the first RS flip-flop.
A gate driving circuit provided by embodiments of the present disclosure comprises a plurality of shift register units provided by embodiments of the present disclosure. A trigger signal received by an S terminal of a first RS flip-flop in the (n+1)-th shift register unit is a signal outputted from a Q terminal of a second RS flip-flop in the n-th shift register unit, n being a positive integer. When n is an odd number, a clock signal received by the n-th shift register unit is a first clock signal; when n is an even number, a clock signal received by the n-th shift register unit is a second clock signal. A frequency of the first clock signal is equal to a frequency of the second clock signal.
A display device provided by embodiments of the present disclosure comprises the gate driving circuit provided by embodiments of the present disclosure.
The shift register unit provided by embodiments of the present disclosure consists of reset-set (RS) flip-flop. The signal outputted by a shift register unit is a signal obtained by shifting the trigger signal received by the shift register unit by half a cycle of the clock signal. Therefore, the signal outputted by the shift register unit provided by embodiments of the present disclosure can serve as a switch signal required by the pixel circuits in the display panel. Moreover, since the shift register unit provided by embodiments of the present disclosure only consists of RS flip-flops, the circuit is simple in structure, which simplifies the manufacturing procedure of the display panel comprising this circuit.
The shift register unit provided by embodiments of the present disclosure only consists of RS flip-flops. The signal outputted by a shift register unit can serve as a switch signal required by a row of pixel circuits in the display panel. Moreover, the circuit is simple in structure, which simplifies the manufacturing procedure of the display panel comprising this circuit.
Specific implementations of the shift register unit, the gate driving circuit and the display device provided by embodiments of the present disclosure are described below with reference to the drawings.
A shift register unit provided by embodiments of the present disclosure comprises, as shown in
A Q terminal of the second RS flip-flop RS2 in a shift register unit is an output terminal OUT of the shift register unit.
When the shift register unit provided by embodiments of the present disclosure is the first shift register unit in the gate driving circuit, the trigger signal received by the S terminal of the first RS flip-flop in the shift register unit provided by embodiments of the present disclosure is a frame start signal STV. When the shift register unit provided by embodiments of the present disclosure is any shift register unit other than the first shift register unit in the gate driving circuit, the trigger signal received by the S terminal of the first RS flip-flop in the shift register unit provided by embodiments of the present disclosure is a signal outputted from an output terminal of a previous-stage shift register unit.
For an active-low RS flip-flop, when the R terminal is at high level, regardless of whether the S terminal is at high level or at low level, the Q terminal is at low level and the U terminal is at high level. When the R terminal is at low level and the S terminal is at high level, the Q terminal is at low level and the
The RS flip-flop in the shift register unit provided by embodiments of the present disclosure may be an RS flip-flop having no inverter at the input terminals (i.e. R terminal and S terminal), and also be an RS flip-flop having inverters at the input terminals.
A gate driving circuit provided by embodiments of the present disclosure comprises, as shown in
The signal outputted from the Q terminal of the second RS flip-flop in each shift register unit in the gate driving circuit is a gate driving signal outputted by the gate driving circuit to respective rows of pixels in the display panel.
Optionally, the first clock signal CLK1 and the second clock signal CLK2 received by the gate driving circuit provided by embodiments of the present disclosure are complementary to each other. That is, when the first clock signal CLK1 is at low level, the second clock signal CLK2 is at high level; when the first clock signal CLK1 is at high level, the second clock signal CLK2 is at low level.
When the first clock signal CLK1 is complementary to the second clock signal CLK2, signals of the Q terminals of respective RS flip-flops in the gate driving circuit shown in
In
In
Optionally, each RS flip-flop in the shift register unit or the gate driving circuit provided by embodiments of the present disclosure comprises, as shown in
One input terminal of the second NOR gate nor2 is connected to the output terminal of the first NOR gate norl, another input terminal of the second NOR gate nor2 is connected to an output terminal of a third NOR gate nor3, and the output terminal of the second NOR gate nor2 is a U terminal of the RS flip-flop.
One input terminal of the third NOR gate nor3 is the R terminal of the RS flip-flop, and another input terminal of the third NOR gate nor3 is an S terminal of the RS flip-flop.
Table 1 below shows a truth table of the RS flip-flop shown in
In light of the truth table shown in Table 1, the waveform diagrams shown in
In the period t1, the R terminal (i.e. CLK1 terminal) of RS1 is at high level, the S terminal (i.e. STV terminal) of RS1 is at high level, and the Q terminal of RS1 is at low level.
In the period t2, the R terminal of RS1 is at low level, the S terminal of RS1 is at high level, and the Q terminal of RS1 maintains the previous state, i.e. remaining at low level.
In the period t3, the R terminal of RS1 is at high level, the S terminal of RS1 is at low level, and the Q terminal of RS1 is at low level.
In the period t4, the R terminal of RS1 is at low level, the S terminal of RS1 is at low level, and the Q terminal of RS1 is at high level.
As for other time periods and other RS flip-flops, the working process is similar to the above process.
Optionally, at least one NOR gate in the RS flip-flop comprises, as shown in
A gate of a first p-type transistor MP1 is one input terminal IN1 of a NOR gate, a first terminal of the first p-type transistor MP1 receives a first voltage signal VDD, and a second terminal of the first p-type transistor MP1 is connected to a first terminal of a second p-type transistor MP2.
A gate of the second p-type transistor MP2 is another input terminal IN2 of the NOR gate, and a second terminal of the second p-type transistor MP2 is an output terminal OUT of the NOR gate.
A gate of a first n-type transistor MN1 is connected to the gate of the second p-type transistor MP2, a first terminal of the first n-type transistor MN1 is the output terminal OUT of the NOR gate, and a second terminal of the first n-type transistor MN1 receives a second voltage signal GND.
A gate of a second n-type transistor MN2 is connected to the gate of the first p-type transistor MP1, a first terminal of the second n-type transistor MN2 is the output terminal OUT of the NOR gate, and a second terminal of the second n-type transistor MN2 receives the second voltage signal GND.
A substrate of the first p-type transistor MP1 is connected to a substrate of the second p-type transistor MP2 and receives the first voltage signal VDD; a substrate of the first n-type transistor MN1 is connected to a substrate of the second n-type transistor MN2 and receives the second voltage signal GND.
Optionally, at least one NOR gate in the RS flip-flop comprises, as shown in
A gate of a first n-type transistor MN1 is one input terminal IN1 of a NOR gate, a first terminal of the first n-type transistor MN1 is an output terminal OUT of the NOR gate, and a second terminal of the first n-type transistor MN1 and a substrate of the first n-type transistor MN1 both receive a second voltage signal GND.
A gate of a second n-type transistor MN2 is another input terminal IN2 of the NOR gate, a first terminal of the second n-type transistor MN2 is the output terminal OUT of the NOR gate, and a second terminal of the second n-type transistor MN2 and a substrate of the second n-type transistor MN2 both receive the second voltage signal GND.
A gate of a third n-type transistor MN3 and a first terminal of the third n-type transistor MN3 both receive a first voltage signal VDD, a second terminal of the third n-type transistor MN3 is connected to a substrate of the third n-type transistor MN3 and is the output terminal OUT of the NOR gate.
Optionally, at least one NOR gate in the RS flip-flop comprises, as shown in
A gate of a first p-type transistor MP1 is one input terminal IN1 of a NOR gate, a first terminal of the first p-type transistor MP1 receives a first voltage signal VDD, and a second terminal of the first p-type transistor MP1 is connected to a first terminal of a second p-type transistor MP2.
A gate of the second p-type transistor MP2 is another input terminal IN2 of the NOR gate, and a second terminal of the second p-type transistor MP2 is an output terminal OUT of the NOR gate.
A substrate of the first p-type transistor MP1 is connected to a substrate of the second p-type transistor MP1 and receives the first voltage signal VDD.
A gate of a third p-type transistor MP3 is connected to a first terminal of the third p-type transistor MP3 and receives a second voltage signal GND, and a second terminal of the third p-type transistor MP3 is connected to a substrate of the third p-type transistor MP3 and is the output terminal OUT of the NOR gate.
The voltage level of the first voltage signal VDD is higher than that of the second voltage signal GND.
The three NOR gates in the RS flip-flop in the shift register unit or the gate driving circuit provided by embodiments of the present disclosure may employ the same structure or different structures.
For a transistor (whether it is an n-type transistor or a p-type transistor) in the display field, there is no clear distinction between the drain and the source. Therefore, the first terminal of the transistor mentioned in embodiments of the present disclosure may be the source (or drain) of the transistor, and the second terminal of the transistor may be the drain (or source) of the transistor. If the source of the transistor is the first terminal, the drain of the transistor is the second terminal. If the drain of the transistor is the first terminal, the source of the transistor is the second terminal.
The display device provided by embodiments of the present disclosure comprises the gate driving circuit provided by embodiments of the present disclosure.
Those skilled in the art can understand that the drawings are just schematic views of exemplary embodiments, and the modules or flows in the drawings may be not necessary to implement the present disclosure.
Those skilled in the art can understand that the modules in a device in an embodiment can be distributed in the device of the embodiment as described by the embodiment, and can also be located in one or more devices different from the present embodiment based on corresponding changes. The modules in the above embodiment can be merged into one module and can also be further split into a plurality of sub modules.
Apparently, those skilled in the art can make various modifications and variations to the present disclosure without departing from the spirit and scope thereof. In this way, if these modifications and variations to the present disclosure fall within the scope of the claims of the present disclosure and equivalent technologies thereof, the present disclosure also intends to encompass these modifications and variations.
Number | Date | Country | Kind |
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201510300522.8 | Jun 2015 | CN | national |
Filing Document | Filing Date | Country | Kind |
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PCT/CN2016/078825 | 4/8/2016 | WO | 00 |