CN100416646C - Pixel unit circuit structure of display panel and driving method - Google Patents

Abstract

A display panel is provided with a plurality of data lines and scanning lines. The scanning lines are arranged in parallel along a first direction, and the data lines are arranged in parallel along a second direction and staggered with the scanning lines. At the intersection of each scan line and the data line, a pixel unit is provided, and each scan line is provided with a switching element. Each switch element determines whether to conduct the common voltage to the pixel unit coupled to the corresponding scan line according to the scan signal transmitted by the corresponding scan line. Therefore, in the present invention, the load of the common voltage can be effectively lightened.

Description

Pixel unit circuit structure and driving method of display panel

technical field

The invention relates to a display panel, and in particular to a display panel capable of reducing the load of a common voltage.

Background technique

For the rapid progress of the multimedia society, most of them benefit from the rapid progress of semiconductor devices or display devices. As far as the display is concerned, the cathode ray tube (Cathode Ray Tube, CRT) has been monopolizing the display market in recent years because of its excellent display quality and economy. However, for the environment where individuals operate most terminals/display devices on the table, or from the perspective of environmental protection, if the trend of energy saving is predicted, cathode ray tubes still have many problems in terms of space utilization and energy consumption, and There is no effective solution to the demands of lightness, thinness, shortness, smallness and low power consumption. Therefore, thin film transistor liquid crystal display (Thin Film Transistor Liquid Crystal Display, hereinafter referred to as TFT-LCD) with superior characteristics such as high picture quality, good space utilization efficiency, low power consumption, and no radiation has gradually become the mainstream of the market.

FIG. 1 is a circuit diagram of the internal structure of a TFT-LCD display panel. Please refer to FIG. 1 , generally speaking, in a display panel of a TFT-LCD, several scanning lines S1˜Sm and data lines D1˜Dn are arranged. Wherein, the scan lines S1˜Sm are arranged parallel to each other along the first direction, while the data lines D1˜Dn are arranged parallel to each other along the second direction and interlaced with the scan lines, and usually the first direction is perpendicular to the second direction. direction. A pixel unit 110 is provided at the intersection of each scan line and data line, thus forming a pixel unit array. The known pixel unit 110 includes a transistor 112 , the gate terminal of which is coupled to the corresponding scan line, the source terminal is coupled to the corresponding data line, and the drain terminal is coupled to the common voltage Vcom through the pixel element 114 . In addition, a storage capacitor 116 is usually provided at both ends of the pixel element 114 to stabilize the voltage across the pixel element 114 .

When the TFT-LCD is to output an image, it first generates a scan signal to one of the scan lines to enable all the pixel units 110 on the scan line. Then the generated video data is sequentially sent to the display panel from the data lines D1 ˜Dn to sequentially drive the enabled pixel units 110 . Assuming that the scan signal is sent in from the scan line S3, all the pixel units 110 on the scan line S3 will be enabled, and then, if the data signal is sent in from the data line D3, it will be sent to the pixels set on the data line D3 and the scan line S3. In the pixel unit 110 at the intersection. At this time, the data signal is turned on from the source terminal to the drain terminal of the transistor 112 to start charging the storage capacitor 114, and the pixel element 114 is turned on due to the voltage difference between the drain terminal of the transistor 112 and the common voltage Vcom.

In a TFT-LCD, the above-mentioned pixel array is formed on a substrate, and the common voltage Vcom is connected to the entire substrate. When one of the pixel units 110 in the pixel array is driven, the load (Loading) to be driven by the common voltage Vcom is not a single pixel unit 110, but equivalent to all the pixel units 110 on the entire pixel array, thus easily causing common The phenomenon that the driving ability of the voltage Vcom is insufficient.

Contents of the invention

Therefore, the purpose of the present invention is to provide a display panel that can reduce the load of the common voltage to improve the driving capability of the common voltage.

Another object of the present invention is to provide a display device that can reduce the load of the common voltage to improve the driving capability of the common voltage.

Another object of the present invention is to provide a driving method of a display panel, which can improve the driving capability of the common voltage.

The invention provides a display panel, which is provided with several data lines and scanning lines. Wherein, the scan lines are arranged parallel to each other along the first direction, and the data lines are arranged parallel to each other and interlaced with the scan lines along the second direction. At the intersection of each scanning line and the data line, a pixel unit is provided, and each scanning line is provided with a switching element. It is worth mentioning that each switching element determines whether to conduct the common voltage to the pixel unit coupled to the corresponding scanning line according to the scanning signal transmitted by the corresponding scanning line.

Wherein, each switching element includes at least one transistor. The gate terminal of the transistor is coupled to the corresponding scanning line, the first source/drain terminal is coupled to the common voltage, and the second source/drain terminal is coupled to the pixel unit on the corresponding scanning line.

In an embodiment of the present invention, the aforementioned pixel unit includes a first transistor, a switch element, a pixel element and a storage capacitor. Wherein, the gate terminal of the first transistor is coupled to one of the scan lines in the display panel to receive the scan signal. The source terminal of the first transistor is coupled to one of the data lines in the display panel. In addition, the drain terminal of the first transistor is coupled to one terminal of the pixel element. It is worth mentioning that, in the display panel of the present invention, the other end of the pixel element is coupled to the common voltage through the switch element coupled to the corresponding scanning line. In addition, the storage capacitor is connected across the two ends of the pixel element.

In another embodiment of the present invention, the pixel unit in the display panel of the present invention includes a first transistor and a second transistor, wherein the gate terminal of the first transistor is coupled to one of the scanning lines in the display panel, to receive scan signals. The source terminal of the first transistor is coupled to one of the data lines in the display panel. The gate terminal and the source terminal of the second transistor are respectively coupled to the gate terminal and the drain terminal of the first transistor. The above-mentioned first and second transistors constitute a well-known double-gate structure. In addition, the present invention also includes a switching element, a pixel element and a storage capacitor, wherein one end of the pixel element is coupled to the drain terminal of the second transistor, and the other end is coupled to a common voltage through the switching element coupled to the corresponding scanning line, The storage capacitor is also connected across the two ends of the pixel element.

In addition, the present invention also provides a display device, which includes a control circuit, a gate driving circuit, a source driving circuit and a display panel. Wherein, the gate driving circuit and the source driving circuit are both coupled to the control circuit, and the gate driving circuit and the source driving circuit are respectively coupled to the display panel through a plurality of scanning lines and data lines to send scanning signals and video signals respectively. data to the display panel. In the display panel, however, multiple pixel units and multiple switch elements are included. Wherein, the pixel units are correspondingly disposed at intersections of each scanning line and data line. The switching elements are correspondingly arranged on the scanning lines respectively. Each switching element determines whether to conduct the common voltage to the pixel units on the corresponding scanning line according to the scanning signal transmitted by the corresponding scanning line.

In addition, the present invention also provides a driving method of a display panel, and the display panel has a plurality of pixel units. The driving method provided by the present invention is as follows. First, a common voltage needs to be provided, and then a scan signal is generated to sequentially enable pixel units, and the common voltage is sent to the enabled pixel units according to the scan signal.

To sum up, in the pixel unit circuit structure of the display panel provided by the present invention, since switching elements made of transistors are provided, and according to the scanning signal received by each pixel unit, it is decided to turn on the common voltage to the pixel element. Therefore, the driving voltage used in the present invention has lighter and less load. In addition, in the driving method provided by the present invention, since the common voltage only needs to be supplied to some enabled pixel units, the load of the common voltage can also be reduced, thereby improving the driving capability of the common voltage. Since the double gate structure can be used in the pixel unit circuit structure of the present invention, the influence of the leakage current can also be reduced.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments of the present invention will be described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 is a circuit diagram of the internal structure of a TFT-LCD display panel.

FIG. 2 is a block diagram of an internal circuit of a display device according to a preferred embodiment of the present invention.

FIG. 3 is an internal circuit diagram of a pixel unit according to a preferred embodiment of the present invention.

FIG. 4 is an internal circuit diagram of a pixel unit according to another embodiment of the present invention.

FIG. 5 is a flowchart of steps of a driving method of a display panel according to a preferred embodiment of the present invention.

Description of main component marking

21, 112, 401, 403: Transistors

110, 212: pixel unit

114, 303, 405: pixel components

116, 305, 407: storage capacitor

210: display panel

214: switch element

232: Control circuit

234: Gate drive circuit

236: Source drive circuit

D1～Dn: data line

D1～Dm: scanning line

Vcom: common voltage

S501, S503, S505: Step flow of the driving method of the display panel

Detailed ways

FIG. 2 is a block diagram of an internal circuit of a display device according to an embodiment of the present invention. Referring to FIG. 2 , the display device provided by the present invention includes a display panel 210 . In the display panel 210 , scan lines G1 ˜ Gm and data lines D1 ˜ Dn are provided. Wherein, the scan lines G1-Gm are arranged parallel to each other along the first direction, and the data lines D1-Dn are arranged parallel to each other along the second direction and interlaced with the scan lines G1-Gm. In general, the first direction is substantially perpendicular to the second direction. At the intersection of each scan line and data line, pixel units such as 212 are provided. In the present invention, a switch circuit such as 214 is provided on each scanning line. Each switch circuit determines whether to conduct the common voltage Vcom to the pixel units on the corresponding scanning line according to the scanning signal transmitted on the corresponding scanning line.

In the following, only the switching element 214 is used to illustrate the structure of the switching element. The switching element used in the present invention may include a transistor 21 as shown in the switching element 214 . Wherein, the first source/drain terminal of the transistor 21 is coupled to the common voltage Vcom, the second source/drain terminal is coupled to the pixel unit on the corresponding scan line (Gm-1), and its gate terminal is coupled to the corresponding scan line line (Gm-1), so that the transistor 21 will conduct the common voltage Vcom to the pixel unit on the corresponding scanning line (Gm-1) according to the scanning signal transmitted on the corresponding scanning line (Gm-1) .

Please continue to refer to FIG. 2 , in the present invention, a control circuit 232 , a gate driving circuit 234 and a source driving circuit 236 are also included. The control circuit 232 is coupled to the gate driving circuit 234 and the source driving circuit 236 to control the gate driving circuit 234 to generate scan signals and send them to the scan lines G1 -Gm in order to enable pixel units on each scan line. In addition, the control circuit 232 also controls the source driving circuit 236 to generate a plurality of video data, and then drives the enabled pixel units through the data lines D1-Dn.

In order to simplify the description, only the pixel unit 212 is taken as an example below to illustrate the structure of the pixel unit used in the present invention.

FIG. 3 is an internal circuit diagram of a pixel unit according to an embodiment of the present invention. Please refer to FIG. 3 , in the pixel unit 212, a transistor 301 is included, the gate terminal of which is coupled to the corresponding scan line (Gm-1) to receive the scan signal generated by the gate drive circuit 234 shown in FIG. 2 , and the source terminal of the transistor 301 is coupled to the corresponding data line ( D1 ). In addition, the drain terminal of the transistor 301 is coupled to one terminal of the pixel element 303 . In addition, the storage capacitor 305 is straddled across the two ends of the pixel element 303 . As we all know, the storage capacitor 305 can be divided into first metal layer/insulation layer/second metal layer (Metal-Insulator-Metal, MIM for short), and first metal layer/insulation layer/indium tin oxide layer (Metal-Insulator-Metal). ITO, referred to as MII) two architectures.

In the present invention, one end of the pixel element 303 is coupled to the drain end of the transistor 301, and the other end is coupled to the switching element (214) through the coupled scanning line (Gm-1) common voltage Vcom. As mentioned above, whether the switching element 214 is turned on or not is determined by the scanning signal transmitted on the corresponding scanning line ( Gm-1 ). In other words, when a scan signal is transmitted on the scan line (Gm-1), the switch element 214 conducts the common voltage Vcom to the pixel units on the scan line Gm-1. Taking the pixel unit 212 as an example, when the switch element 214 is turned on, the common voltage Vcom is turned on to the pixel element 203 .

FIG. 4 is an internal circuit diagram of a pixel unit according to another embodiment of the present invention. Please refer to FIG. 4 , in another alternative embodiment, the pixel unit can also be implemented with a double gate structure. Taking the pixel unit 212 as an example, it includes transistors 401 and 403 . Wherein, the gate of the transistor 401 is coupled to the scan line Gm-1, and the source terminal of the transistor 401 is coupled to the data line D1. In addition, the drain terminal and the gate terminal of the transistor 403 are respectively coupled to the source terminal and the gate terminal of the transistor 401 . The drain terminal of the transistor 403 is coupled to one terminal of the pixel element 405 , and the pixel element 405 is equivalent to the pixel 303 in FIG. 3 . Likewise, in this embodiment, the pixel unit 212 further includes a storage capacitor 407 connected across the two ends of the pixel element 405 . Same as shown in FIG. 3 , one end of the pixel element 405 is coupled to the drain end of the transistor 403 , and the other end is also coupled to the common voltage Vcom through the switching element 214 .

Because the circuit structure of the pixel unit shown in FIG. 4 is a double-gate structure. Therefore, this embodiment can effectively reduce the impact of the leakage current on the pixel element 405 .

In addition, both the above-mentioned transistors 401 and 403 can be realized by using low-temperature polysilicon thin film transistors.

FIG. 5 is a flowchart of steps of a driving method of a display panel according to a preferred embodiment of the present invention. Referring to FIG. 5 , the driving method provided by the present invention can be applied to the display panel 210 shown in FIG. 2 , for example. In the driving method of the present invention, first, as described in step S501, the common voltage Vcom in FIG. 2 and FIG. 3 is provided, and then the control circuit 232 shown in FIG. 2 can control the gate and drive circuit 234 as described in step S503 A scan signal is generated and sent into each scan line in turn to enable the pixel unit coupled thereto. Taking FIG. 2 as an example, assuming that the scan signal is sent to the scan line Gm-1, all pixel units disposed on the scan line Gm-1 will be enabled. In the present invention, since each scanning line is provided with a switching circuit (such as shown in FIG. 2 ), as described in step S505, when the pixel unit is enabled, the common voltage will be based on the scanning signal At the same time, it is sent to the enabled pixel unit.

In addition, in the present invention, after the common voltage is sent to the enabled pixel unit, for example, the control circuit 232 in FIG. Drive the enabled pixel unit.

To sum up, in the present invention, the common voltage is sent to the corresponding pixel unit according to the scan signal. That is to say, the common voltage only drives the pixel units on one scan line at a time. Therefore, the load of the common voltage in the present invention is equivalent to only one scanning line. Therefore, the present invention can effectively reduce the load of the common voltage, and further improve the driving capability of the common voltage.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some changes and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the claims.

Claims (8)

1. display panel is characterized in that comprising:

The multi-strip scanning line is along the first direction setting that is arranged in parallel with each other;

Many data lines, parallel to each other and be crisscross arranged along second direction with above-mentioned sweep trace;

A plurality of pixel cells are arranged at each above-mentioned sweep trace and each above-mentioned data line confluce; And

A plurality of on-off elements, corresponding respectively above-mentioned sweep trace and being provided with, and each above-mentioned on-off element is the sweep signal that sweep trace transmitted according to correspondence, and whether decision is with the common electric voltage conducting above-mentioned pixel cell on the sweep trace of correspondence extremely; Wherein, each above-mentioned on-off element is a transistor, and its gate terminal couples the sweep trace of correspondence, and its first source/drain electrode end couples this common electric voltage, and its second source/drain electrode end then couples the above-mentioned pixel cell on the sweep trace of correspondence.

2. display panel according to claim 1 is characterized in that each above-mentioned pixel cell comprises:

Transistor, its gate terminal couple in the above-mentioned sweep trace, and in order to receive sweep signal, the source terminal of this transistor then couples in the above-mentioned data line;

Pixel element, an end couples the drain electrode end of this transistor, and the other end then is coupled to this common electric voltage by the on-off element that sweep trace coupled of correspondence; And

Storage capacitors is connected across the two ends of this pixel element.

3. display panel according to claim 1 is characterized in that each above-mentioned pixel cell comprises:

The first transistor, its gate terminal couple in the above-mentioned sweep trace, and in order to receive this sweep signal, the source terminal of this first transistor then couples in the above-mentioned data line;

Transistor seconds, its gate terminal and source terminal couple each other with the gate terminal and the drain electrode end of this first transistor respectively;

Pixel element, an end couples the drain electrode end of this transistor seconds, and the other end then is coupled to this common electric voltage by the on-off element that sweep trace coupled of correspondence; And

Storage capacitors is connected across the two ends of this pixel element.

4. display equipment is characterized in that comprising:

Control circuit;

Gate driver circuit couples this control circuit, and sends a plurality of sweep signals by the multi-strip scanning line;

Source electrode drive circuit couples this control circuit, and sends a plurality of video datas by many data lines; And

Display panel is coupled to this gate driver circuit by above-mentioned sweep trace, and is coupled to this source electrode drive circuit by above-mentioned data line, and this display panel comprises:

A plurality of pixel cells, correspondence is arranged at the confluce of each above-mentioned sweep trace and each above-mentioned data line respectively; And

A plurality of on-off elements, corresponding respectively above-mentioned sweep trace and being provided with, and each above-mentioned on-off element is the sweep signal that sweep trace transmitted according to correspondence, and whether decision is with the common electric voltage conducting above-mentioned pixel cell on the sweep trace of correspondence extremely; Wherein, each above-mentioned switch is a transistor, and its gate terminal couples the sweep trace of correspondence, and its first source/drain electrode end couples this common electric voltage, and its second source/drain electrode end then couples the above-mentioned pixel cell on the sweep trace of correspondence.

5. display equipment according to claim 4 is characterized in that each above-mentioned pixel cell all comprises thin film transistor (TFT).

6. display equipment according to claim 4 is characterized in that each above-mentioned pixel cell all comprises low-temperature polysilicon film transistor.

7. the driving method of a display panel it is characterized in that this display panel has a plurality of pixel cells, and this driving method comprises the following steps:

Common electric voltage is provided;

Produce sweep signal and come the above-mentioned pixel cell of activation successively; And

According to this sweep signal this common electric voltage delivered to and to state pixel cell on being enabled; Wherein, one on-off circuit is set on each sweep trace, wherein comprises transistor as on-off element, its gate terminal couples the sweep trace of correspondence, its first source/drain electrode end couples this common electric voltage, and its second source/drain electrode end then couples the above-mentioned pixel cell on the sweep trace of correspondence.

8. the driving method of display panel according to claim 7 is characterized in that also comprising producing a plurality of video datas, and correspondence is delivered to and stated pixel cell on being enabled respectively.

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