TWI451389B - Liquid crystal display and method of driving a common voltage - Google Patents

Description

Liquid crystal display and common voltage driving method thereof

The present invention relates to a liquid crystal display and a method of driving the same.

Due to its low radiation, light weight, short power consumption and low power consumption, liquid crystal displays are becoming more and more widely used, and with the maturity and innovation of related technologies, their types are becoming more and more diverse.

Please refer to FIG. 1 , which is a schematic diagram of a circuit structure of a prior art liquid crystal display. The liquid crystal display 10 includes a liquid crystal panel 11, a scan driver 13, a data driver 14, and a common voltage generator 15. The scan driver 13 and the data driver 14 are used to drive the liquid crystal panel 11. The common voltage generator 15 is for supplying a common voltage to the liquid crystal panel 11.

The liquid crystal panel 11 includes a plurality of parallel scan lines 131, a plurality of parallel data lines 141 that are perpendicularly insulated from the scan lines 131, a common voltage line 101, and a plurality of pixel units 102.

Each of the pixel units 102 includes a thin film transistor 1021, a liquid crystal capacitor 1022, and a storage capacitor 1023 at the intersection of the scan line 131 and the data line 141.

Each of the liquid crystal capacitors 1022 is composed of a pixel electrode 1025, a common electrode 1026, and a liquid crystal layer (not shown) sandwiched therebetween. Each storage capacitor 1023 includes the pixel electrode 1025, a storage capacitor electrode 1027, and an insulating material sandwiched therebetween.

A gate (not labeled) of the thin film transistor 1021 is coupled to the scan line 131, a source (not labeled) is coupled to the data line 141, and a drain (not labeled) is coupled to the pixel electrode 1025.

When the liquid crystal display 10 is in normal operation, the scan driver 13 sequentially supplies a plurality of scan signals to the scan line 131, and the plurality of thin film transistors 1021 connected to the scan lines 131 are sequentially turned on. When the scan line 131 is scanned, the data driver 14 supplies a complex gray scale voltage to the complex data line 141. The gray scale voltage is applied to the pixel electrode 1025 via the source and drain of the correspondingly turned on thin film transistor 1021.

The storage capacitor electrode 1027 and the common electrode 1026 of the liquid crystal capacitor 1022 share a common voltage, which is provided by the common voltage generator 15 via the common voltage line 101. The common voltage is typically a 5V DC voltage.

Generally, the common voltage of the liquid crystal display 10 is affected by various coupling capacitances to generate a ripple, thereby causing crosstalk of the display screen of the liquid crystal display 10. Therefore, the display quality of the liquid crystal display 10 is degraded.

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

In view of the above, it is necessary to provide a common voltage driving method for the above liquid crystal display.

A liquid crystal display includes a liquid crystal panel including a first common voltage line, a second common voltage line, a common electrode line, a plurality of liquid crystal capacitors, and a plurality of storage capacitors, each liquid crystal capacitor including a common electrode, each storage capacitor A storage capacitor electrode is included. A common voltage generator that provides a common voltage to the storage capacitor electrode via the first common voltage line. At least one common voltage regenerator receives the feedback common voltage of the storage capacitor electrode via the second common voltage line, and generates a regenerative common voltage according to the feedback common voltage, and then applies to the common electrode via the common electrode line.

A common voltage driving method for a liquid crystal display, the liquid crystal display comprising a liquid crystal panel comprising a plurality of liquid crystal capacitors and a plurality of storage capacitors, each liquid crystal capacitor comprising a common electrode, each storage capacitor comprising a storage capacitor electrode, the common voltage driving The method includes the steps of: the common voltage generator providing a common voltage to the storage capacitor electrode; the common voltage regenerator receiving a feedback common voltage of the storage capacitor electrode; the common voltage regenerator providing a regeneration common according to the received feedback common voltage Voltage to the common electrode.

In contrast to the prior art, the liquid crystal display and its common voltage driving method of the present invention include a common voltage regenerator that supplies a common voltage to the common electrode. Since the common voltage supplied to the common electrode contains an inverted sharp wave, the inverted sharp wave cancels the sharp wave generated by the coupling action on the common electrode, so that the common voltage of the liquid crystal capacitor remains stable. Therefore, the display screen of the liquid crystal display does not cause crosstalk, so that the liquid crystal display has a high quality when displaying a picture.

2 is a schematic structural view of a first embodiment of a liquid crystal display device of the present invention. The liquid crystal display 20 includes a liquid crystal panel 21. The liquid crystal panel 21 includes a first glass substrate 210, a second glass substrate 220 disposed opposite to each other, and a liquid crystal layer (not shown) sandwiched between the two glass substrates 210 and 220.

The first glass substrate 210 includes a common electrode 240 located on a side of the first glass substrate 210 adjacent to the liquid crystal layer.

The second glass substrate 220 includes a first common voltage line 204, a second common voltage line 205, a common electrode line 206, a plurality of mutually parallel scan lines 221, a plurality of parallel lines parallel to each other and perpendicularly insulated from the scan lines 221 The data line 222 and the plurality of pixel electrodes 223 and the plurality of storage capacitors 224 are formed in a region where the complex scanning line 221 and the complex data line 222 intersect perpendicularly.

The pixel electrode 223, the common electrode 240, and a liquid crystal layer (not shown) sandwiched therebetween constitute a liquid crystal capacitor 225.

Each storage capacitor 224 is composed of the pixel electrode 223, a storage capacitor electrode 226, and an insulating material sandwiched therebetween.

The first common voltage line 204 and the second common voltage line 205 are electrically connected to the storage capacitor electrode 226 via internal traces. The first common voltage line 204 and the second common voltage line 205 are respectively located on opposite sides of the second glass substrate 220 and are parallel to the data line 222.

The common electrode 240 and the second glass substrate 220 are electrically connected via a conductive silver paste 227 disposed on the second glass substrate 220. The conductive silver paste 227 is respectively disposed at the upper left corner, the upper right corner, the lower left corner, and the lower right corner of the second glass substrate 220. The common electrode line 206 is located on four sides of the second glass substrate 220, and is electrically connected to the conductive silver paste 227.

Please refer to FIG. 3 together, which is a schematic diagram of the circuit structure of the liquid crystal display 20. The liquid crystal display 20 further includes a data driver 24, a scan driver 23, a common voltage generator 25, and a common voltage regenerator 26.

The scan driver 23 is configured to provide a scan voltage for the complex scan line 221, and the data driver 24 is configured to provide a data voltage for the complex data line 222.

The common voltage generator 25 includes a common voltage output 251 that is electrically coupled to the first common voltage line 204. The common voltage output terminal 204 provides a common voltage to the storage capacitor electrode 226 via the first common voltage line 204. The common voltage is a 5V DC voltage.

The common voltage regenerator 26 includes a common voltage input 266, a feedback common voltage input 267, and a regenerative common voltage output 268. The feedback common voltage input terminal 267 is electrically coupled to the second common voltage line 205, and receives the feedback common voltage of the storage capacitor electrode 226 via the second common voltage 205 line. The common voltage input 266 is electrically coupled to the common voltage output 251 of the common voltage generator 25. The regenerative common voltage output terminal 268 is electrically coupled to the common electrode line 206, and the common electrode 240 is supplied with a regenerative common voltage via the common electrode line 206 and the conductive silver paste 227.

Please refer to FIG. 4 together, which is a schematic diagram of the circuit structure of the common voltage regenerator 26. The common voltage regenerator 26 further includes an operational amplifier 261, a first resistor 262, a second resistor 263, and a DC blocking capacitor 264. The feedback common voltage input terminal 267 is sequentially connected to the inverting input terminal of the operational amplifier 261 via the DC blocking capacitor 264 and the first resistor 262. The output of the operational amplifier 261 is electrically coupled to the regenerative common voltage output 268. The regenerative common voltage output 268 is electrically coupled to the inverting input of the operational amplifier 261 via the second resistor 263. The feedback common voltage input 266 is electrically coupled to the non-inverting input of the operational amplifier 261.

When the liquid crystal display 20 is in operation, the common voltage output terminal 251 of the common voltage generator 25 supplies a 5V DC voltage to the common voltage input terminal 266 of the common voltage regenerator 26. At the same time, the common voltage output terminal 251 provides a 5V DC common voltage for the storage capacitor electrode 226 via the first common voltage line 204.

The feedback common voltage input terminal 267 receives the feedback common voltage on the storage capacitor electrode 226 via the second common voltage line 205, and the feedback common voltage has a sharp wave. The feedback common voltage is applied by the DC blocking capacitor 264, and the sharp wave component passes through the DC blocking capacitor 264, and is loaded to the inverting input terminal of the operational amplifier 261 via the first resistor 262. The regenerative common voltage output 268 outputs a regenerative common voltage having an inverted spike. The regenerative common voltage is applied to the common electrode 240 via the common electrode line 206 and the conductive silver paste 227, thereby eliminating the sharp wave of the common electrode 240, so that the common electrode 240 maintains a stable DC voltage of 5V.

Adjusting the first resistor 262 and the second resistor 263 can adjust the amplitude of the spike so that the amplitude of the inverted spike of the regenerative common voltage is the same as the amplitude of the spike of the feedback common voltage.

Please refer to FIG. 5 , which is a schematic structural diagram of a circuit of a second embodiment of the liquid crystal display of the present invention. The liquid crystal display 30 differs from the liquid crystal display 20 of the first embodiment only in that the liquid crystal display 30 includes a first common voltage regenerator 361, a second common voltage regenerator 362, a third common voltage regenerator 363, and A fourth common voltage regenerator 364. The first, second, third, and fourth common voltage regenerators 361, 362, 363, and 364 respectively include a first regenerative common voltage output terminal 365, a second regenerative common voltage output terminal 366, and a third regeneration common The voltage output terminal 367 and a fourth regenerative common voltage output terminal 368 receive the same feedback common voltage. However, the first and second resistors of the four common voltage regenerators 361, 362, 363, and 364 are different, respectively, such that the four regenerative common voltage output terminals 365, 366, 367, and 368 output inverted spikes having different amplitudes. Regeneration of the common voltage. The common electrode line 306 is disconnected into four independent segments. The four common electrode lines 306 are electrically connected to the conductive silver paste of the upper left corner, the lower left corner, the upper right corner and the lower right corner of a liquid crystal panel.

The four regenerative common voltage output terminals 365, 366, 367 and 368 respectively supply a regenerative common voltage for the independent four-segment common electrode line 306, thereby respectively providing a regenerative common voltage for four different regions of the common electrode of the liquid crystal panel. Since the common voltage of each region of the common electrode of the liquid crystal panel is different by the capacitive coupling effect, the amplitude of the common voltage of each region is different, and it is better to divide the liquid crystal panel into four regions to provide a regenerative common voltage. Eliminate the sharp waves of the common 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 those skilled in the art will be able to make equivalent modifications or changes in accordance with the spirit of the present invention. It should be covered by the following patent application.

LCD Monitor. . . 20, 30

Silver glue. . . 227

LCD panel. . . twenty one

The first common voltage line. . . 204

Scan drive. . . twenty three

The second common voltage line. . . 205

Data drive. . . twenty four

Common electrode line. . . 206, 306

Common voltage generator. . . 25

Operational Amplifier. . . 261

Public voltage regenerator. . . 26

First resistance. . . 262

The first glass substrate. . . 210

Second resistance. . . 263

Second glass substrate. . . 220

DC blocking capacitor. . . 264

Common electrode. . . 240

Common voltage input. . . 266

Scan line. . . 221

Feedback common voltage input. . . 267

Data line. . . 222

The first common voltage regenerator. . . 361

Pixel electrode. . . 223

Second common voltage regenerator. . . 362

Storage capacitor. . . 224

The third public voltage regenerator. . . 363

Liquid crystal capacitors. . . 225

Fourth common voltage regenerator. . . 364

226‧‧‧ storage capacitor electrode

268, 365, 366, 367, 368‧‧ ‧ regenerative common voltage output

10‧‧‧LCD display

101‧‧‧Common voltage line

102‧‧‧ pixel unit

1021‧‧‧film transistor

1022‧‧‧Liquid Crystal Capacitor

1023‧‧‧ Storage Capacitor

1025‧‧‧ pixel electrodes

1026‧‧‧Common electrode

1027‧‧‧ Storage Capacitor

11‧‧‧LCD panel

13‧‧‧Scan Drive

131‧‧‧ scan line

14‧‧‧Data Drive

141‧‧‧Information line

15‧‧‧Common voltage generator

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

2 is a schematic structural view of a first embodiment of a liquid crystal display of the present invention.

3 is a schematic view showing the circuit structure of the liquid crystal display of FIG. 2.

4 is a schematic diagram showing the circuit structure of the common voltage regenerator of FIG.

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

LCD Monitor. . . 20

Common electrode. . . 240

LCD panel. . . twenty one

Common voltage output. . . 251

Scan drive. . . twenty three

Feedback common voltage input. . . 267

Data drive. . . twenty four

Common voltage input. . . 266

Common voltage generator. . . 25

Regeneration of the common voltage output. . . 268

Public voltage regenerator. . . 26

The first common voltage line. . . 204

Scan line. . . 221

The second common voltage line. . . 205

Data line. . . 222

Common electrode line. . . 206

Storage capacitor electrode. . . 226

Claims (15)

A liquid crystal display comprising: a liquid crystal panel comprising a first common voltage line, a second common voltage line, a common electrode line, a plurality of liquid crystal capacitors and a plurality of storage capacitors, each liquid crystal capacitor comprising a common electrode, each a storage capacitor includes a storage capacitor electrode; a common voltage generator that supplies a common voltage to the storage capacitor electrode via the first common voltage line; and at least one common voltage regenerator that receives the storage via the second common voltage line The capacitor electrode feeds back a common voltage, and generates a regenerative common voltage according to the feedback common voltage, and then applies to the common electrode via the common electrode line. The liquid crystal display of claim 1, wherein the common voltage generator is electrically connected to the storage capacitor electrode via the first common voltage line, the common voltage regenerator comprising a feedback common voltage input terminal, a common a voltage input terminal and a regenerative common voltage output terminal, wherein the feedback common voltage input terminal is electrically connected to the storage capacitor electrode via the second common voltage line, and the common voltage input terminal is electrically connected to the common voltage generator, the common voltage output terminal The terminal is connected to the common electrode via the common electrode line. The liquid crystal display according to claim 2, wherein the common voltage regenerator further comprises an operational amplifier, a DC blocking capacitor, a first resistor and a second resistor, wherein the feedback common voltage input terminal is in turn The first resistor is electrically connected to the inverting input terminal of the operational amplifier via the DC blocking capacitor, and the output end of the operational amplifier is electrically connected to the regenerative common voltage output terminal, and the regenerative common voltage output terminal is electrically connected via the second resistor Connected to the inverting input, the common voltage input is electrically coupled to the non-inverting input of the operational amplifier. The liquid crystal display of claim 1, wherein the first common voltage line and the second common voltage line are respectively located on opposite sides of the liquid crystal panel. The liquid crystal display of claim 1, wherein the feedback common voltage received by the common voltage regenerator has a sharp wave, and the common voltage regenerator outputs a sharp wave of the regenerated common voltage and the tip of the feedback common voltage The waves have opposite phases and the same amplitude. The liquid crystal display of claim 1, wherein the common electrode line is located between the edge of the liquid crystal panel and the first common voltage line, and between the edge of the liquid crystal panel and the second common voltage line. The liquid crystal display of claim 1, wherein the liquid crystal panel is provided with a conductive silver paste at four corners thereof, and the common electrode line is located on four sides of the liquid crystal panel, and is electrically connected to the conductive silver paste. The liquid crystal display of claim 7, wherein the at least one common voltage regenerator is a four common voltage regenerator, and the common electrode line is disconnected four segments, which are respectively electrically connected to the conductive silver paste. The four common voltage regenerators respectively provide a regenerative common voltage for the four segment common electrode lines. A common voltage driving method for a liquid crystal display, the liquid crystal display comprising a liquid crystal panel comprising a plurality of liquid crystal capacitors, a plurality of storage capacitors, and a common electrode line, each liquid crystal capacitor comprising a common electrode, each storage capacitor comprising a storage capacitor An electrode, the common voltage driving method includes the steps of: a common voltage generator providing a common voltage to the storage capacitor electrode; at least one common voltage regenerator receiving a feedback common voltage of the storage capacitor electrode; the at least one common voltage regenerator receiving The feedback common voltage thereto provides a regenerative common voltage to the common electrode via the common electrode line. The public voltage driving method of the liquid crystal display of claim 9, wherein the liquid crystal panel further comprises a first common voltage line, the common voltage generator supplies a common voltage to the storage via the first common voltage line Capacitor electrode, which is a 5V DC voltage. The method of driving a common voltage of a liquid crystal display according to claim 10, wherein the liquid crystal panel further comprises a second common voltage line, the common voltage regenerator receiving the storage capacitor electrode via the second common voltage line A common voltage is fed back, and the feedback common voltage has a sharp wave. The common voltage driving method of a liquid crystal display according to claim 11, wherein the common voltage regenerator simultaneously receives a common voltage of the common voltage generator. The common voltage of the liquid crystal display as described in claim 12 The driving method, wherein the regenerative common voltage has a sharp wave, and the sharp wave of the feedback common voltage is opposite to the sharp wave of the regenerative common voltage, and the amplitude is the same. The common voltage driving method for a liquid crystal display according to claim 9, wherein the at least one common voltage regenerator is a four common voltage regenerator, and the four common voltage regenerators respectively provide four different regions of the liquid crystal panel. Regenerate the common voltage. The common voltage driving method of the liquid crystal display according to claim 9, wherein the common electrode line is located between the edge of the liquid crystal panel and the first common voltage line, and is located at an edge of the liquid crystal panel and the second common Between voltage lines.