TWI393108B - Liquid crystal display device and method for driving same - Google Patents

Description

Liquid crystal display device and driving method thereof

The present invention relates to a liquid crystal display device and a driving method.

Liquid crystal display devices have been widely used in electronic devices such as personal computers because of their advantages such as lightness, high brightness, and low radiation. However, at the moment of power-on, due to the unstable working signal transmitted, the liquid crystal display device may be disturbed, which may cause undesirable phenomena such as boot noise.

Please refer to FIG. 1 , which is a schematic diagram of a circuit structure of a prior art liquid crystal display device. The liquid crystal display device 1 includes a power supply circuit 11, a panel power supply circuit 12, a drive control circuit 13, a data drive circuit 14, a scan drive circuit 15, and a display panel 16. The display panel 16 includes a plurality of pixel units (not labeled), and each of the pixel units includes a thin film transistor (not labeled) and a liquid crystal capacitor (not labeled).

The power supply circuit 11 provides an operating voltage for the panel power supply circuit 12 and the drive control circuit 13. The drive control circuit 13 outputs a scan control signal to the scan drive circuit 15 and outputs a clock pulse voltage signal to the data drive circuit 14. The scan driving circuit 15 scans the display panel 16 based on the scan control signal. The data driving circuit 14 outputs a data signal to the display panel 16 according to the clock pulse voltage signal.

The panel power supply circuit 12 converts the operating voltage supplied from the power supply circuit 11 into a gate-on voltage VGH (High-Level Gate Voltage) and a gate-off voltage VGL (Low-Level Gate Voltage) required to drive the scan driving circuit 15. And driving the data driving circuit 14 The required main operating voltage, AVDD. Wherein, the main working voltage AVDD is a high voltage or high current output of the thin film transistor of the display panel, and the voltage value is usually +5.xV or +12.xV; the gate conduction voltage VGH is used to bias the thin film transistor The high voltage output, the voltage value is usually +15.xV or +24.xV; the gate cutoff voltage VGL is the reverse voltage output of the reverse bias of the thin film transistor, and its voltage value is usually -10.xV or -6.xV, x is any natural number.

Please refer to FIG. 2 together, which is a timing diagram of the output voltage signal of the panel power supply circuit 12 during the startup of the liquid crystal display device 1. After receiving the operating voltage outputted by the power supply circuit 11, the panel power supply circuit 12 outputs the main operating voltage AVDD required to drive the data driving circuit 14. Next, the panel power supply circuit 12 outputs a gate-off voltage VGL to the scan driving circuit 15. Finally, the panel power supply circuit 12 outputs a gate-on voltage VGH to the scan driving circuit 15.

The panel power supply circuit 12 and the drive control circuit 13 of the liquid crystal display device 1 cooperate to provide the display panel 11 with the required operating voltage and operation signal, thereby enabling the liquid crystal display device 1 to display normally.

During the startup of the liquid crystal display device 1, after the panel power supply circuit 12 outputs the main operating voltage AVDD to the data driving circuit 14, the data driving circuit 14 receives the gate-off voltage VGL before outputting the gate-off voltage VGL to the scan driving circuit 15. The main operating voltage AVDD is prepared to output a data signal to the display panel 16 according to the clock pulse voltage signal outputted by the driving control circuit 13. The scan driving circuit 15 does not receive the gate cutoff voltage VGL, and thus cannot completely turn off the thin film power of the display panel 16. Crystal.

However, after receiving the main working voltage AVDD, the data driving circuit 14 outputs a noise signal to the display panel 16 due to a malfunction, and the noise signal charges the liquid crystal capacitor of the display panel 16 by the thin film transistor. Therefore, when the liquid crystal display device 1 is turned on, a flickering phenomenon occurs, and the display quality of the liquid crystal display device 1 is poor.

In view of this, it is necessary to provide a liquid crystal display device having a good display quality.

In view of the above, it is also necessary to provide a liquid crystal display device driving method with better display quality.

A liquid crystal display device includes a display panel, a plurality of switching elements, a driving module and a detection control circuit. The drive module generates a voltage signal. The driving module drives the display panel by the plurality of switching elements. The detection control circuit detects a voltage signal of the driving module and controls the plurality of switching elements.

A liquid crystal display device driving method, comprising the steps of: providing a display panel for displaying various screens; providing a driving module for generating a voltage signal; providing a plurality of switching elements, wherein the driving module drives the plurality of switching elements a display panel; providing a detection circuit that detects a voltage signal of the driving module and controls the plurality of switching elements.

In the liquid crystal display device and the driving method of the present invention, when the liquid crystal display device is turned on, the plurality of switching elements can output the noise signal outputted by the driving module to the display panel, and stabilize the switching element in each voltage signal After the opening, the liquid crystal display device is normally displayed. The display of the liquid crystal display device caused by the noise signal at the time of starting up is reduced to improve the display quality of the liquid crystal display device.

Please refer to FIG. 3 , which is a schematic structural diagram of a circuit of a first embodiment of a liquid crystal display device of the present invention. The liquid crystal display device 2 includes a driving module 29, a detection control circuit 26, a display panel 27, and a plurality of switching elements 28. The driving module 29 includes a power circuit 21, a panel power circuit 22, a driving control circuit 23, a data driving circuit 24, and a scan driving circuit 25.

The power circuit 21 includes a power output 211.

The panel power circuit 22 includes a power input terminal 221, a main operating voltage output terminal 222, a gate turn-on voltage output terminal 223, and a gate turn-off voltage output terminal 224. The power input terminal 221 is electrically connected to the power output terminal 211 of the power circuit 21.

The drive control circuit 23 includes a control power input terminal 231, a clock signal output terminal 232, and a scan signal output terminal 233. The control power input terminal 231 is electrically connected to the power output terminal 211 of the power circuit 21.

The data driving circuit 24 includes a main operating voltage input terminal 241, a clock signal input terminal 242 and a plurality of data signal output terminals 243. The main operating voltage input terminal 241 is electrically coupled to the main operating voltage output terminal 222 of the panel power supply circuit 22. The clock signal input terminal 242 is electrically coupled to the clock signal output terminal 232 of the drive control circuit 23.

The scan driving circuit 25 includes a gate turn-on voltage input terminal 251, A gate cutoff voltage input terminal 252, a scan signal input terminal 254 and a plurality of scan output terminals 253. The gate-on voltage input terminal 251 is electrically connected to the gate-on voltage output terminal 223 of the panel power supply circuit 22. The gate cutoff voltage input terminal 252 is electrically coupled to the gate cutoff voltage output terminal 224 of the panel power supply circuit 22. The scan signal input terminal 254 is electrically connected to the scan signal output terminal 233 of the drive control circuit 23.

The switching element 28 includes a switch control terminal 281. The switching element 28 is a normally closed switching element. When the switching element 28 is not applied with a control signal to the switching control terminal 281, the switching element 28 is turned off.

The display panel 27 includes a plurality of data lines 271 and a plurality of scan lines 272. The plurality of data lines 271 are electrically connected to the data signal output terminal 243 of the data driving circuit 24 by the plurality of switching elements 28, respectively. The plurality of scan lines 272 respectively correspond to the plurality of scan output ends 253 electrically connected to the scan drive circuit 25.

The detection control circuit 26 includes a detection terminal 261 and a control output 262. The detection control circuit 26 internally includes a detection circuit 263 and a delay circuit 264. The detecting terminal 261 is electrically connected to the clock signal output terminal 232 of the driving control circuit 23. The control output 262 is electrically coupled to the switch control terminal 281 of the plurality of switching elements 28.

The working principle of the liquid crystal display device 2 is as follows: The power supply circuit 21 generates a power supply voltage and outputs the power supply output terminal 211 to the panel power supply circuit 22.

After receiving the power voltage, the panel power circuit 22 first generates a main operating voltage AVDD, and outputs the main operating voltage output 222 to the The data driving circuit 24; then, the panel power supply circuit 22 generates a gate-off voltage VGL, and outputs the gate-off voltage output terminal 224 to the scan driving circuit 25; finally, the panel power circuit 22 generates a gate. The voltage VGH is turned on and output to the scan driving circuit 25 via the gate-on voltage output terminal 223.

The driving control circuit 23 receives the synchronization signal input from an external circuit (not shown) and analyzes the synchronization signal, and stably outputs the main operating voltage AVDD, the gate-off voltage VGL and the gate-on voltage in the panel power supply circuit 22. After VGH, a scan signal and a clock pulse voltage signal are generated according to the synchronization signal. The scan signal is output to the scan driving circuit 25 via the scan signal output terminal 233. The clock pulse voltage signal is output to the data driving circuit 24 via the clock signal output terminal 232.

The scan driving circuit 25 receives the scan signal and scans the display panel 27 according to the scan signal.

The data driving circuit 24 receives the clock pulse voltage signal. During the pulse period of the clock pulse signal, the rising edge of the clock pulse signal causes the data driving circuit 24 to read the data signal from an external circuit (not shown); the falling edge of the clock pulse signal causes the data driving circuit The data signal output terminal 243 and the switching element 28 output the data signal to the display panel 27.

The display panel 27 displays various image messages under the cooperative driving of the scan driving circuit 25 and the data driving circuit 24.

The detection terminal 261 of the detection control circuit 26 receives the clock pulse voltage signal output from the clock signal output terminal 232 of the drive control circuit 23. The inspection The clock circuit voltage input from the detecting terminal 261 is measured by the measuring circuit 263. When the detecting circuit 263 detects the rising edge of the clock pulse signal, it outputs a control signal. The delay circuit 264 delays the control signal outputted by the detection circuit 263 for a certain period of time, and then outputs the control output 262 to the switch control terminal 281 of the complex switching element 28. The control signal causes the switching element 28 to be turned on, so that the data signal outputted by the data driving circuit 24 can be output to the plurality of data lines 271 of the display panel 27, so that the display panel 27 displays various image information.

Compared with the prior art, the liquid crystal display device 2 of the present invention first causes the liquid crystal display device 2 to obtain the main operating voltage AVDD from the data driving circuit 24 to the scan driving circuit 25 to obtain the gate by the normally closed switching element 28. During the period of the cutoff voltage VGL, the noise signal outputted from the complex data signal output terminal 243 cannot be output to the display panel 27, and the switching element 28 is turned on after the voltage signals are stabilized, so that the liquid crystal display device 2 is normal. display. When the power-on signal is turned on, the liquid crystal display device 2 is turned on and blinked due to the mischarge of the liquid crystal capacitor by the thin film transistor which is not completely turned off in the display panel 27, thereby improving the display quality of the liquid crystal display device 2.

Please refer to FIG. 4 , which is a schematic structural diagram of a circuit of a second embodiment of a liquid crystal display device of the present invention. The liquid crystal display device 3 of the second embodiment is substantially the same as the liquid crystal display device 2 of the first embodiment, and the difference is that the detection control circuit 36 includes a first detecting end 361, a second detecting end 365, and a comparison. Circuit 363, a delay circuit 364 and a control output 362. The first and second detecting ends 361 and 365 are electrically connected to the panel power supply The main operating voltage output terminal 322 and the gate turn-on voltage output terminal 323 of the circuit 32.

The working principle of the liquid crystal display device 3 is as follows: the first and second detecting ends 361 and 365 respectively receive the gate-on voltage VGH outputted by the gate-on voltage output terminal 323 and the main operation of the output of the main operating voltage output terminal 322. The voltage AVDD, the comparison circuit 363 compares the magnitudes of the voltages of the gate-on voltage VGH and the main operating voltage AVDD input from the first and second detecting terminals 361 and 365, respectively, when the gate-on voltage VGH is higher than the main operation. When the voltage AVDD is large, the comparison circuit 363 outputs a control signal. The delay circuit 364 delays the control signal output from the comparison circuit 363 for a certain period of time and outputs it to the switch control terminal 381 of the complex switching element 38 to turn on the plurality of switching elements 38.

Compared with the liquid crystal display device 2 of the first embodiment, the detection circuit 36 of the liquid crystal display device 3 directly detects changes in the main operating voltage AVDD and the gate-on voltage VGH to control the plurality of switching elements. In the first embodiment, the drive control circuit 23 can be prevented from being erroneously caused to cause the plurality of switching elements 28 to be turned on prematurely.

Please refer to FIG. 5 , which is a schematic structural diagram of a circuit of a third embodiment of a liquid crystal display device of the present invention. The liquid crystal display device 4 of the third embodiment is substantially the same as the liquid crystal display device 2 of the first embodiment, and the difference is that the detection control circuit 46 includes a delay circuit 464, and the detection terminal 461 of the detection control circuit 46 is electrically The gate of the panel power supply circuit 42 is connected to the voltage output terminal 423. The detection control circuit 46 directly uses the stable gate-on voltage outputted from the gate-on voltage output terminal 423 as a control signal. The inspection The delay circuit of the measurement control circuit 46 delays the control signal and outputs it to the switch control terminal 481 of the plurality of switching elements 48 to turn on the plurality of switching elements 48.

Compared with the liquid crystal display device 3 of the second embodiment, the detection control circuit 46 of the liquid crystal display device 4 has only one detecting end 461, and has only one delay circuit 464 therein, so that the circuit is relatively simple and convenient for circuit design and manufacture.

However, the present invention is not limited to the above embodiments. For example, the delay circuit 264, 364 or 464 is a timing delay circuit, and the delay circuit 264, 364 or 464 may also be an RC delay circuit; the detection circuit 263 and the The control signal outputted by the comparison circuit 363 is a voltage signal having the same voltage value as the gate conduction voltage.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only the preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention are It should be covered by the following patent application.

Power output ‧‧‧211

Power circuit ‧‧21.

Power input ‧‧‧221

Gate cut-off voltage output ‧‧‧252

Drive control circuit ‧‧23

Main working voltage output ‧‧‧222,322

Data drive circuit ‧‧24

Gate cut-off voltage output ‧‧‧224

Clock signal input ‧‧‧242

Control power input ‧‧‧231

Scanning drive circuit ‧‧25

Scanning signal output ‧‧‧233

Scanning output ‧‧‧253

Main working voltage input ‧‧‧241

Information line ‧‧‧271

Data signal output ‧‧‧243

Control output ‧‧‧262

Gate turn-on voltage input ‧‧‧251

Second detection end ‧‧‧365

Scanning signal input ‧‧‧254

First detection end ‧‧‧361

Display panel ‧‧27

Comparison circuit ‧‧‧363

Scanning line ‧‧‧272

Detection circuit ‧‧‧263

Detection side ‧‧‧261,461

Drive module ‧‧29

Gate turn-on voltage output ‧‧‧223, 323, 423

Detection control circuit ‧‧‧26, 36, 46

Delay circuit ‧‧‧264, 364, 464

Switch control terminal ‧‧‧281, 381, 481

Liquid crystal display device ‧‧2,3,4

Panel power circuit ‧‧22,32,42

Clock signal output ‧‧‧232

Switching elements ‧‧‧28, 38, 48

1 is a schematic diagram showing the circuit structure of a prior art liquid crystal display device.

2 is a timing diagram of output voltage signals of the panel power supply circuit during the startup of the liquid crystal display device shown in FIG. 1.

3 is a schematic view showing the circuit structure of a first embodiment of a liquid crystal display device of the present invention.

4 is a schematic view showing the circuit structure of a second embodiment of the liquid crystal display device of the present invention.

Fig. 5 is a schematic view showing the circuit structure of a third embodiment of the liquid crystal display device of the present invention.

Liquid crystal display device ‧‧2

Power circuit ‧‧21.

Power output ‧‧‧211

Panel power circuit ‧‧22

Power input ‧‧‧221

Main working voltage output ‧‧‧222

Gate turn-on voltage output ‧‧‧223

Gate cut-off voltage output ‧‧‧224

Drive control circuit ‧‧23

Control power input ‧‧‧231

Clock signal output ‧‧‧232

Scanning signal output ‧‧‧233

Data drive circuit ‧‧24

Main working voltage input ‧‧‧241

Clock signal input ‧‧‧242

Data signal output ‧‧‧243

Scanning drive circuit ‧‧25

Gate turn-on voltage input ‧‧‧251

Gate cut-off voltage output ‧‧‧252

Scanning signal input ‧‧‧254

Scanning output ‧‧‧253

Display panel ‧‧27

Information line ‧‧‧271

Scanning line ‧‧‧272

Detection control circuit ‧‧26

Detection side ‧‧‧261

Control output ‧‧‧262

Detection circuit ‧‧‧263

Delay circuit ‧‧‧264

Switching element ‧‧‧28

Switch control terminal ‧‧‧281

Drive module ‧‧29

Claims (16)

A liquid crystal display device comprising: a display panel; a plurality of switching elements; a driving module that generates a voltage signal, the driving module drives the display panel by the plurality of switching elements; and a detection control circuit that detects the driving module The voltage control signal includes a delay circuit that delays the control signal and outputs the same to the plurality of switching elements. The liquid crystal display device of claim 1, wherein the driving module comprises a data driving circuit, and the data driving circuit outputs a data signal to the display panel by the plurality of switching elements. The liquid crystal display device of claim 2, wherein the driving module further comprises a driving control circuit, wherein the detecting control circuit comprises a detecting circuit, and the driving control circuit outputs a clock pulse voltage signal to control the data driving circuit. And outputting a data signal, wherein the voltage signal detected by the detection control circuit is the clock pulse voltage signal, and the detecting circuit detects a rising edge of the clock pulse voltage signal and outputs a control signal, and the control signal turns on the plurality of switching elements. The liquid crystal display device of claim 2, wherein the driving module further comprises a scan driving circuit and a panel power supply circuit, wherein the scan driving circuit scans the display panel, the panel power supply circuit includes a gate On voltage output terminal, one gate cutoff voltage input And a main working voltage output end, wherein the panel power supply circuit provides a gate turn-on voltage and a gate turn-off voltage of the scan driving circuit by the gate turn-on voltage output terminal and the gate turn-off voltage output terminal, respectively, and A main operating voltage of the data driving circuit is provided by the main working voltage output terminal. The liquid crystal display device of claim 4, wherein the detection control circuit comprises a comparison circuit. The comparison circuit compares the gate on voltage output end of the panel power supply circuit and the output voltage value of the main working voltage output terminal, and determines whether to output a control signal for turning on the plurality of switching elements according to the comparison result. The liquid crystal display device of claim 5, wherein the comparison circuit outputs the control signal when a voltage value outputted by the gate-on voltage output terminal is greater than the main operating voltage output terminal. The liquid crystal display device of claim 4, wherein the gate on-voltage outputted by the gate-on voltage output terminal of the panel power supply circuit directly turns on the plurality of switching elements by delaying the delay circuit. The liquid crystal display device of claim 7, wherein the delay circuit is an RC delay circuit or a timing delay circuit. A liquid crystal display device driving method, comprising the steps of: providing a display panel for displaying various screens; providing a driving module for generating a voltage signal; providing a plurality of switching elements, wherein the driving module drives the plurality of switching elements Display panel Providing a detection circuit for detecting a voltage signal of the driving module and outputting a control signal, the detection control circuit comprising a delay circuit, wherein the delay signal delays the control signal and outputs the control signal to the plurality of switching elements; wherein the driving module comprises a data driving circuit and a driving control circuit, the data driving circuit outputs a data signal to the display panel by the plurality of switching elements, the driving control circuit outputs a clock pulse voltage signal to control the data driving circuit to output a data signal, the detecting circuit After detecting the rising edge of the clock pulse signal, a control signal is output, and the control signal turns on the plurality of switching elements. The liquid crystal display device driving method of claim 9, wherein the driving module further comprises a scan driving circuit that scans the display panel. The driving method of the liquid crystal display device of claim 10, wherein the driving module further comprises a panel power supply circuit, the panel power supply circuit comprising a gate conduction voltage output terminal, a gate cutoff voltage output terminal, and a gate a main working voltage output end, the panel power supply circuit respectively provides a gate turn-on voltage and a gate turn-off voltage of the scan driving circuit by the gate turn-on voltage output terminal and the gate turn-off voltage output terminal, and the main work is performed by the main working voltage The voltage output terminal provides a main operating voltage of the data driving circuit. The method of driving a liquid crystal display device according to claim 11, wherein the detection control circuit comprises a comparison circuit. The comparison circuit compares the gate conduction voltage output end of the panel power supply circuit and the main work The circuit compares the gate conduction voltage output end of the panel power supply circuit and the output voltage value of the main working voltage output terminal, and determines whether to output a control signal for turning on the plurality of switching elements according to the comparison result. The liquid crystal display device driving method of claim 12, wherein the comparison circuit outputs the control signal when a voltage value outputted by the gate-on voltage output terminal is greater than the main operating voltage output terminal. The liquid crystal display device driving method of claim 13, wherein the detection control circuit further comprises a delay circuit, wherein the delay signal delays the control signal and outputs the signal to the plurality of switching elements. The liquid crystal display device driving method of claim 11, wherein the detection control circuit comprises a delay circuit, and the gate conduction voltage outputted by the gate conduction voltage output terminal of the panel power supply circuit is delayed by the delay circuit The plurality of switching elements are directly controlled to turn on the plurality of switching elements. The method of driving a liquid crystal display device according to claim 15, wherein the delay circuit is an RC delay circuit.